RFR: JDK-8261203: Incorrectly escaped javadoc html with type annotations

[Jonathan Gibbons]

Please review a simple change to exclude type annotations from primitive types in the id generated for a method signature.

There's a latent secondary issue, not addressed here, that quotes (`"`) in an attribute value are not escaped correctly. That could be fixed, separately, at the cost of checking every generated attribute value. For now, at least for ids, we can avoid this issue by constraining the set of attribute values, which for ids, is now easier, in the recently-new `HtmlIds` class.

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Commit messages:
 - JDK-8261203: Incorrectly escaped javadoc html with type annotations

Changes: https://git.openjdk.java.net/jdk/pull/2719/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2719&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8261203
  Stats: 88 lines in 2 files changed: 86 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2719.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2719/head:pull/2719

PR: https://git.openjdk.java.net/jdk/pull/2719