RFR: 8263102: Expand documention of Method.isBridge [v6]

[Joe Darcy]

> The existing documentation of Method.isBridge isn't terribly helpful to the reader. This RFE proposes to given a common example of how bridge methods are used. The JLS does *not* have a section discussing bridge methods in detail; bridge methods are a compilation technique for lowering the Java language to the JVM, they are not a language feature per se. The example given is not exhaustive; there can be and are other uses of bridge methods.
> 
> Once the text is agreed to; I'll update the copyright year as well.

Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:

  Respond to review feedback, reflow paragraphs, update copyrights.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2852/files
  - new: https://git.openjdk.java.net/jdk/pull/2852/files/0425a2f3..97c59502

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2852&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2852&range=04-05

  Stats: 29 lines in 3 files changed: 0 ins; 1 del; 28 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2852.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2852/head:pull/2852

PR: https://git.openjdk.java.net/jdk/pull/2852