fix: README.md images (#1673)

On GitHub, Markdown does not show images if urls are redirected.

README.md

@@ -815,7 +815,7 @@ Product.search("milk", boost_where: {orderer_ids: current_user.id})
 
 Autocomplete predicts what a user will type, making the search experience faster and easier.
 
-![Autocomplete](https://gist.github.com/ankane/b6988db2802aca68a589b31e41b44195/raw/40febe948427e5bc53ec4e5dc248822855fef76f/autocomplete.png)
+![Autocomplete](https://gist.githubusercontent.com/ankane/b6988db2802aca68a589b31e41b44195/raw/40febe948427e5bc53ec4e5dc248822855fef76f/autocomplete.png)
 
 **Note:** To autocomplete on search terms rather than results, check out [Autosuggest](https://github.com/ankane/autosuggest).
 
@@ -881,7 +881,7 @@ Then add the search box and JavaScript code to a view.
 
 ## Suggestions
 
-![Suggest](https://gist.github.com/ankane/b6988db2802aca68a589b31e41b44195/raw/40febe948427e5bc53ec4e5dc248822855fef76f/recursion.png)
+![Suggest](https://gist.githubusercontent.com/ankane/b6988db2802aca68a589b31e41b44195/raw/40febe948427e5bc53ec4e5dc248822855fef76f/recursion.png)
 
 ```ruby
 class Product < ApplicationRecord
@@ -900,7 +900,7 @@ products.suggestions # ["peanut butter"]
 
 [Aggregations](https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations.html) provide aggregated search data.
 
-![Aggregations](https://gist.github.com/ankane/b6988db2802aca68a589b31e41b44195/raw/40febe948427e5bc53ec4e5dc248822855fef76f/facets.png)
+![Aggregations](https://gist.githubusercontent.com/ankane/b6988db2802aca68a589b31e41b44195/raw/40febe948427e5bc53ec4e5dc248822855fef76f/facets.png)
 
 ```ruby
 products = Product.search("chuck taylor", aggs: [:product_type, :gender, :brand])