fix(Cabal): Removes the short -g option for the --ghc flag

[zlonast]

fix: #2056

I think we can simply redefine the flag, and few people will notice, since it doesn't appear in libraries or executables.

Those who do notice will now use the full flag. As I understand it, these are the people who manually enter flags in the console.

Currently, this is mostly LLM, which makes this change even more valuable for them.

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