[Chapel Merge] Set 2.9 to release mode

Branch: refs/heads/main
Revision: d284f9cb710d16b48e7339b73e6fd1d413e7b532
Author: arifthpe
Link: Set 2.9 to release mode by arifthpe · Pull Request #28967 · chapel-lang/chapel · GitHub
Log Message:
Set 2.9 to release mode (#28967)

Update version numbering in the codebase to reflect the official 2.9
release.

Corresponding PR for previous release for reference:

To be merged on 2.9 code freeze day, June 10.

[reviewed by @benharsh , thanks!]

Testing:

  • manually checked everything matches the previous release's PR

Compare: Comparing fd27c9210e63c04b4a7c95378992d0042f083c28...1fb7a00efb8c2b4bf8360e23b3accda8a534122a · 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/28967.diff