RFR: JDK-8283234: Improve @jls usage in java.base

[Joe Darcy]

Checking the java.bases sources revealed a number of other instances where conceptual links into the JLS (or JVMS) could be upgraded to actual links.

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Commit messages:
 - JDK-8283234: Improve @jls usage in java.base

Changes: https://git.openjdk.java.net/jdk/pull/7834/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7834&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283234
  Stats: 21 lines in 5 files changed: 0 ins; 0 del; 21 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7834.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7834/head:pull/7834

PR: https://git.openjdk.java.net/jdk/pull/7834