[Chapel Merge] Update docs for Chapel enviroment variables

Branch: refs/heads/main
Revision: 3bc41a0ed87439f56f204b9488d0921531852564
Author: jabraham17
Link: Update docs for Chapel enviroment variables by jabraham17 · Pull Request #25212 · chapel-lang/chapel · GitHub
Log Message:
Update docs for Chapel enviroment variables (#25212)

Updates chplenv.rst to include CHPL_TARGET_JEMALLOC=system (does not
show in rendered docs) and CHPL_HWLOC=system.

This documentation should now reflect changes from the following PRs

Built and viewed docs locally

[Reviewed by @jhh67 and @bonachea]

Compare: Comparing 88f00b850c09e8116ac559190a496a0d58a34a5f...c51eaf7a99507b791a86ad65aa5032eddca1fcf7 · chapel-lang/chapel · GitHub

Diff:
M doc/rst/usingchapel/chplenv.rst
https://github.com/chapel-lang/chapel/pull/25212.diff