RFR: Fix javadoc generation and add check to testing suite [v2]

[James Yuzawa]

> Motivation: There is bad javadoc being generated. This fixes that and also adds a check to the testing suite to make sure it does not happen again.
> 
> Notes: I branched off of jdk22 branch since I would like such fixes to make their way into the jdk22 branch. Please let me know if there is a different base or head I should use.

James Yuzawa has updated the pull request incrementally with one additional commit since the last revision:

  Fix javadoc generation and add check to testing suite
  
  Motivation: There is bad javadoc being generated. This fixes that and also adds a check to the testing suite to make sure it does not happen again.

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

Changes:
  - all: https://git.openjdk.org/jextract/pull/227/files
  - new: https://git.openjdk.org/jextract/pull/227/files/bc8c9371..6a8c77c7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jextract&pr=227&range=01
 - incr: https://webrevs.openjdk.org/?repo=jextract&pr=227&range=00-01

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jextract/pull/227.diff
  Fetch: git fetch https://git.openjdk.org/jextract.git pull/227/head:pull/227

PR: https://git.openjdk.org/jextract/pull/227