Fix linkes to material ui website

Author: fzaninotto

UPGRADE.md

@@ -318,7 +318,7 @@ import CardActions from '@material-ui/core/CardActions';
 
 Following the same path as Material UI, react-admin now uses [JSS](https://github.com/cssinjs/jss) for styling components instead of the `style` prop. This approach has many benefits, including a smaller DOM, faster rendering, media queries support, and automated browser prefixing.
 
-All react-admin components now accept a `className` prop instead of the `elStyle` prop. But it expects a CSS *class name* instead of a CSS object. To set custom styles through a class name, you must use the [`withStyles` Higher Order Component](https://material-ui-next.com/customization/css-in-js/#api) supplied by Material-UI.
+All react-admin components now accept a `className` prop instead of the `elStyle` prop. But it expects a CSS *class name* instead of a CSS object. To set custom styles through a class name, you must use the [`withStyles` Higher Order Component](https://material-ui.com/customization/css-in-js/#api) supplied by Material-UI.
 
 ```diff
 - import { EmailField, List, Datagrid } from 'admin-on-rest';
@@ -389,7 +389,7 @@ In addition to `elStyle`, Field and Input components used to support a `style` p
 // </td>
 ```
 
-Furthermore, some React-admin components such as the `List`, `Filter`, and `Datagrid` also accept a `classes` prop. This prop is injected by the [`withStyles` Higher Order Component](https://material-ui-next.com/customization/css-in-js/#api) and allows you to customize the style of some deep children. See the Theming documentation for details.
+Furthermore, some React-admin components such as the `List`, `Filter`, and `Datagrid` also accept a `classes` prop. This prop is injected by the [`withStyles` Higher Order Component](https://material-ui.com/customization/css-in-js/#api) and allows you to customize the style of some deep children. See the Theming documentation for details.
 
 **Tip**: When you set the `classes` prop in the `List` or `Datagrid` components, you might see warnings about the `cell` and `field` classes being unknown by those components. Those warnings are not displayed in `production` mode, and are just a way to ensure you know what you're doing. And you can make them disappear by destructuring the `classes` prop:
 

docs/Admin.md

@@ -266,7 +266,7 @@ const App = () => (
 
 ![Dark theme](./img/dark-theme.png)
 
-For more details on predefined themes and custom themes, refer to the [Material UI Customization documentation](https://material-ui-next.com/customization/themes/).
+For more details on predefined themes and custom themes, refer to the [Material UI Customization documentation](https://material-ui.com/customization/themes/).
 
 ## `appLayout`
 

docs/Fields.md

@@ -739,7 +739,7 @@ import { UrlField } from 'react-admin';
 
 ## Styling Fields
 
-All field components accept a `className` prop, allowing you to customize their style to your liking. We advise you to use the Material UI styling solution, JSS, to generate those classes. See their [documentation](https://material-ui-next.com/customization/css-in-js/#api) about that.
+All field components accept a `className` prop, allowing you to customize their style to your liking. We advise you to use the Material UI styling solution, JSS, to generate those classes. See their [documentation](https://material-ui.com/customization/css-in-js/#api) about that.
 
 {% raw %}
 ```jsx

docs/List.md

@@ -272,7 +272,7 @@ It does so by inspecting its `context` prop.
 
 **Tip**: Don't mix up this `filters` prop, expecting a React element, with the `filter` props, which expects an object to define permanent filters (see below).
 
-The `Filter` component accepts the usual `className` prop but you can override many class names injected to the inner components by React-admin thanks to the `classes` property (as most Material UI components, see their [documentation about it](https://material-ui-next.com/customization/overrides/#overriding-with-classes)). This property accepts the following keys:
+The `Filter` component accepts the usual `className` prop but you can override many class names injected to the inner components by React-admin thanks to the `classes` property (as most Material UI components, see their [documentation about it](https://material-ui.com/customization/overrides/#overriding-with-classes)). This property accepts the following keys:
 
 * `form`: applied to the root element when rendering as a form.
 * `button`: applied to the root element when rendering as a button.
@@ -421,7 +421,7 @@ export const PostList = (props) => (
 
 ### CSS API
 
-The `List` component accepts the usual `className` prop but you can override many class names injected to the inner components by React-admin thanks to the `classes` property (as most Material UI components, see their [documentation about it](https://material-ui-next.com/customization/overrides/#overriding-with-classes)). This property accepts the following keys:
+The `List` component accepts the usual `className` prop but you can override many class names injected to the inner components by React-admin thanks to the `classes` property (as most Material UI components, see their [documentation about it](https://material-ui.com/customization/overrides/#overriding-with-classes)). This property accepts the following keys:
 
 * `root`: alternative to using `className`. Applied to the root element.
 * `header`: applied to the page header
@@ -537,7 +537,7 @@ export const PostList = (props) => (
 
 ### CSS API
 
-The `Datagrid` component accepts the usual `className` prop but you can override many class names injected to the inner components by React-admin thanks to the `classes` property (as most Material UI components, see their [documentation about it](https://material-ui-next.com/customization/overrides/#overriding-with-classes)). This property accepts the following keys:
+The `Datagrid` component accepts the usual `className` prop but you can override many class names injected to the inner components by React-admin thanks to the `classes` property (as most Material UI components, see their [documentation about it](https://material-ui.com/customization/overrides/#overriding-with-classes)). This property accepts the following keys:
 
 * `table`: alternative to using `className`. Applied to the root element.
 * `tbody`: applied to the tbody

packages/ra-core/src/actions/notificationActions.js

@@ -11,7 +11,7 @@ export const SHOW_NOTIFICATION = 'RA/SHOW_NOTIFICATION';
  * @param {string} message - A translatable label or text to display on notification
  * @param {string} [type=info] - The type of the notification
  * @param {notificationOptions} [notificationOptions] - Specify additional parameters of notification
- * @see {@link https://material-ui-next.com/api/snackbar/|Material ui snackbar component}
+ * @see {@link https://material-ui.com/api/snackbar/|Material ui snackbar component}
  * @see {@link https://material.io/guidelines/components/snackbars-toasts.html|Material ui reference document on snackbar}
  * 
  */

packages/ra-ui-materialui/README.md

@@ -1,6 +1,6 @@
 # ra-ui-material
 
-UI Components for [react-admin](https://marmelab.com/react-admin/) with [MaterialUI](https://material-ui-next.com/).
+UI Components for [react-admin](https://marmelab.com/react-admin/) with [MaterialUI](https://material-ui.com/).
 
 ## License