Fix Windows Emscripten build instructions to use Ninja generator when building cppinterop-tblgen

[mcbarton]

https://github.com/compiler-research/CppInterOp/pull/928/changes didn't include the documentation changes so that users locally could replicate the build.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.82%. Comparing base (61e4c60) to head (6222905).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #934   +/-   ##
=======================================
  Coverage   80.82%   80.82%           
=======================================
  Files          15       15           
  Lines        4710     4710           
=======================================
  Hits         3807     3807           
  Misses        903      903           

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[vgvassilev]

The build instructions are too volatile and too often buggy or out of date. I'd propose to point to the github actions links so that people get the real picture. Now this should be sufficiently cleaned up for users to look at.

[mcbarton]

The build instructions are too volatile and too often buggy or out of date. I'd propose to point to the github actions links so that people get the real picture. Now this should be sufficiently cleaned up for users to look at.

I personally don't think the documentation to often buggy, and I don't know where this assertion has come from. I certaintly can't stop you pointing the user to the github ci for them to reverse engineer the build instructions, but I certaintly don't think its a good idea, since this will hard for beginner looking to contribute (I say this as someone who had to do that when I first contributed to this project given the documentation was very incomplete then). Its been very disheartening for me recently to see the route this project has been taking whatever Gemini, Claude, etc spits out as gospel and more clear. I find it very demotivating feeling that any contributions I make to this project in the future will likely very soon not receive a human review. Apologies for the way this comment may come accross, but I thought it best for myself if I let my feelings be known.