RFR: Fix simple warnings [v2]

[Jorn Vernee]

On Sun, 7 Apr 2024 16:51:18 GMT, Nir Lisker <nlisker at openjdk.org> wrote:

>> Fixes for warnings:
>> 
>> * Missing `@Override` annotations
>> * Unnecessary code (casts and semicolons)
>> * Unused imports
>> 
>> There are more complicated warnings that should be looked at separately like resource leaks, potential null access, and unused variables.
>
> Nir Lisker has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add newline

Looks good. Thanks for the cleanups.

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Marked as reviewed by jvernee (Committer).

PR Review: https://git.openjdk.org/jextract/pull/229#pullrequestreview-1985249820