[Chapel Merge] More info on UDP xSocket errors

Branch: refs/heads/master
Revision: 9adf4a2
Author: vasslitvinov
Log Message:

Merge pull request #16566 from vasslitvinov/more-info-for-udp-error

More info on UDP xSocket errors

Added a couple of details to the UDP platform note
that may be of help to developers.

While there, switched to code-block:: text to avoid bash highlighting.

r: @ronawho @e-kayrakli - thank you!

Modified Files:
M doc/rst/platforms/udp.rst

Compare: https://github.com/chapel-lang/chapel/compare/18c570f057ac...9adf4a24c8ad