Add MethodSpec.Builder.clearModifiers() method

[ash211]

Before this PR

Can't easily migrate palantir/safe-logging's usage pattern here because Palantir javapoet made MethodSpec.Builder.modifiers to be append-only, but that usage clears the modifiers.

After this PR

==COMMIT_MSG==
Add MethodSpec.Builder.clearModifiers() method
==COMMIT_MSG==

Possible downsides?

None known

[changelog-app]

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• feature: A new feature of the service.
• improvement: An incremental improvement in the functionality or operation of the service.
• fix: Remedies the incorrect behaviour of a component of the service in a backwards-compatible way.
• break: Has the potential to break consumers of this service's API, inclusive of both Palantir services
  and external consumers of the service's API (e.g. customer-written software or integrations).
• deprecation: Advertises the intention to remove service functionality without any change to the
  operation of the service itself.
• manualTask: Requires the possibility of manual intervention (running a script, eyeballing configuration,
  performing database surgery, ...) at the time of upgrade for it to succeed.
• migration: A fully automatic upgrade migration task with no engineer input required.

Note: only one type should be chosen.

How are new versions calculated?

• ❗The break and manual task changelog types will result in a major release!
• 🐛 The fix changelog type will result in a minor release in most cases, and a patch release version for patch branches. This behaviour is configurable in autorelease.
• ✨ All others will result in a minor version release.

Type

• Feature
• Improvement
• Fix
• Break
• Deprecation
• Manual task
• Migration

Description

Add MethodSpec.Builder.clearModifiers() method

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[pkoenig10]

I'd prefer not to add destructive methods to builders. If you need to remove items previously added to a builder, just start a new builder.

[pkoenig10]

Can't easily migrate palantir/safe-logging's usage pattern here

In this particular case, it sounds like we probably want to change the return type of createLoggerBridge() to more properly what we need. For example, changing it from a TypeSpec to a method-less TypeSpec along with modifier-less MethodSpecs, for example.