RFR: 8287753: [spelling] close well-established compounds

[Pavel Rappo]

This is a spelling and terminology PR, not a code PR. Rationale for some of the changes are as follows:

* "Subsignature" is mentioned in JLS 8.4.2 Method Signature.
* lower- and upper- bounded wrt `super` and `extends` are mentioned in JLS 4.10.5 Type Projections.
* For "super super class" I used a great-grandparent analogy as I'm unaware of any rules on repeated prefixes in English.
* "subkind" is used on two more occasions a few lines above that change

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.java.net/jdk/pull/9007/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=9007&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8287753
  Stats: 40 lines in 18 files changed: 0 ins; 0 del; 40 mod
  Patch: https://git.openjdk.java.net/jdk/pull/9007.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/9007/head:pull/9007

PR: https://git.openjdk.java.net/jdk/pull/9007