[Chapel Merge] Reduce use of `index.html`

Branch: refs/heads/main
Revision: a4357daa9d53ecc6d957680082cf76f1b0cacc30
Author: bradcray
Link: Reduce use of `index.html` by bradcray · Pull Request #26583 · chapel-lang/chapel · GitHub
Log Message:
Reduce use of index.html (#26583)

[reviewed by @arezaii — thanks!]

This PR removes a number of instances of index.html files from our
docs and code, motivated by:

  • making URLs shorter, simpler, and more canonical
  • reducing the number of index.html files I find when grepping the
    website for instances of it

Interestingly, I think there are many remaining uses in the generated
docs which, I'm guessing, are inserted by sphinx, though it seems
surprising that it wouldn't use directories rather than explicit
index.html files…

Compare: Comparing 7b9011c1d0732fb54a316a327eb819003adbe3e1...53a7bb6b654e90962f97fbcb8941ea1e82684269 · chapel-lang/chapel · GitHub

Diff:
M CHANGES.md
M doc/Makefile.sphinx
M doc/rst/developer/bestPractices/GettingStarted.rst
M doc/rst/developer/bestPractices/README.md
M doc/rst/developer/chips/inactive/14.rst
M doc/rst/language/archivedSpecs.rst
M doc/rst/technotes/gpu.rst
M util/buildRelease/changePrerelease
https://github.com/chapel-lang/chapel/pull/26583.diff