[Chapel Merge] Update documentation to reflect the new record `ha

Branch: refs/heads/main
Revision: acd390f
Author: bmcdonald3
Log Message:

Merge pull request #18545 from bmcdonald3/hash-docs

Update documentation to reflect the new record hash special method

In #18343 the functionality to override the map hash function by defining a myRecord.hash method was added, but I didn't add any docs in that PR since I was (unreasonably) scared to add docs for the first time. This PR adds that documentation and updates the special methods primer to reflect that change.

[reviewed by @mppf - thank you!]

Closes Cray/chapel-private#2533

Modified Files:
M doc/rst/language/spec/records.rst

M test/release/examples/primers/specialMethods.chpl
M test/release/examples/primers/specialMethods.good

Compare: https://github.com/chapel-lang/chapel/compare/4c78dd81eaa6...acd390f888b0