RFR: 8339115: Rename TypeKind enum constants to follow code style

[Jonathan Gibbons]

On Tue, 27 Aug 2024 22:15:17 GMT, Chen Liang <liach at openjdk.org> wrote:

> `TypeKind` enum constants are named in wrong code style; correct them before finalization.
> 
> Also improved `TypeKind` specification to talk about not mentioned `returnType`, `void`, and subword types being erased to int (and how). See the associated CSR too.
> 
> See the HTML output for the changed `JSpec` taglet's `6.5.newarray` rendering: https://cr.openjdk.org/~liach/8339115-typekind/java.base/java/lang/classfile/TypeKind.html
> 
> Note: when reviewing, please use https://cr.openjdk.org/~iris/se/23/spec/draft/java-se-23-draft-spec-37/ instead of JVMS 22 for reference; JVMS 23 has fixed a few ambiguities about subword types being absent from JVM's stack and locals.

Changes to JSpec.java look OK.

No comment on other changes.

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

PR Review: https://git.openjdk.org/jdk/pull/20737#pullrequestreview-2264584894