Resolve #7765: Add -c alias for --constraint cli argument

[phadej]

---

Please include the following checklist in your PR:

• Patches conform to the coding conventions.
• Any changes that could be relevant to users have been recorded in the changelog.
• The documentation has been updated, if necessary.

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[Mikolaj]

LGTM

[fgaz]

Please update doc/cabal-project.rst too

[phadej]

Please update doc/cabal-project.rst too

How? It is documenting the cabal.project file. There you still have to write constraints: ....

setup-commands has mention of

.. option:: -f flagname or -f -flagname

    Force the specified flag to ``true`` or ``false`` (if preceded with
    a ``-``). Later specifications for the same flags will override
    earlier, i.e., specifying ``-fdebug -f-debug`` is equivalent to
    ``-f-debug``

.. option:: --flags=flagspecs

    Same as ``-f``, but allows specifying multiple flag assignments at

But this PR doesn't change Setup.hs flags, and I don't know where the cabal-install CLI interface is documented?

[fgaz]

here is where I was thinking. as far as I understand, cabal-project.rst documents both cabal.project and cli options. For example here are a couple with a shorthand: https://cabal.readthedocs.io/en/3.6/cabal-project.html#cfg-flag---flags https://cabal.readthedocs.io/en/3.6/cabal-project.html#cfg-flag---jobs

I might be wrong though. I'll retract the review, so you can merge if that's the case

[phadej]

[phadej]

ping