Fix JavaDoc style for several WebView classes

This fixes the JavaDoc style for the following classes ...
- CacheManager.java
- CookieManager.java
- GeolocationPermissions.java
- WebResourceResponse.java
- WebSettings.java
- WebStorage.java
- WebView.java

In particular, this applies the guidelines at
https://wiki.corp.google.com/twiki/bin/view/Main/APIDocumentation

This should help to ensure that future JavaDoc comments use correct style,
rather than using incorrect style for consistency.

Note that this change does not attempt to improve the content of the JavaDoc
comments. This will be done in later changes.

Bug: 5461416
Change-Id: I79e9b15a8cf3597195d58e154a7eb1bcc462944c