[Chapel Merge] Changing version numbers for 1.26.0 release

Branch: refs/heads/main
Revision: e25993a
Author: tzinsky
Link: Unavailable
Log Message:

Merge pull request #19469 from tzinsky/version-1.26-no-prerelease

Changing version numbers for 1.26.0 release.

Modified Files:
M compiler/main/version_num.h

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/compflags/bradc/printstuff/versionhelp.sh

Compare: https://github.com/chapel-lang/chapel/compare/8457fea985e9...e25993a69cc6