RFR: JDK-8278318: Create {@index} entries for key LangTools terms [v2]

[Jonathan Gibbons]

> Please review a small update to the `jdk.compiler` and `java.compiler` module declarations, to index the names of some key compiler-related APIs.
> 
> There are no API changes, so no CSR is required.

Jonathan Gibbons has updated the pull request incrementally with one additional commit since the last revision:

  update copyright years

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6729/files
  - new: https://git.openjdk.java.net/jdk/pull/6729/files/2cc1c3e4..3f9c9a40

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6729&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6729&range=00-01

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6729.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6729/head:pull/6729

PR: https://git.openjdk.java.net/jdk/pull/6729