[Chapel Merge] Set 2.7 to release mode

Branch: refs/heads/main
Revision: 7ae8ca93c2f63546335d88d6bb1a2b70dc10a7e2
Author: arifthpe
Link: https://github.com/chapel-lang/chapel/pull/28175
Log Message:
Set 2.7 to release mode (#28175)

Update version numbering in the codebase to reflect the official 2.7
release.

Corresponding PR for previous release for reference:

To be merged on 2.7 code freeze day, December 10.

[reviewed by @jabraham17, thanks!]

Testing:

  • manually checked everything matches the previous release's PR

Compare: Comparing ab87e395c1ffb97a0f3d3eafe8f55ff322bff367...0a416841c5036197980c396b27c083b8dc1f75f6 · chapel-lang/chapel · GitHub

Diff:
M CMakeLists.txt
M doc/rst/conf.py
M doc/rst/language/archivedSpecs.rst
M doc/rst/usingchapel/QUICKSTART.rst
M doc/rst/usingchapel/chplenv.rst
M man/confchpl.rst
M man/confchpldoc.rst
M test/chpldoc/compflags/combinations/versionhelp-chpldoc.sh
M test/compflags/bradc/printstuff/versionhelp.sh
https://github.com/chapel-lang/chapel/pull/28175.diff