Remove generic anchors from the dev guide (#16655)

Summary of the issue:
When the dev guide was converted to md, generic anchors have been created for headings that had no anchor in the t2t file. Probably needed for the table of contents.
However these new anchors have generic names ({#toc123}). It would be better to use more explicit names as done for other already referenced headings.

Description of user facing changes
None

Description of development approach
Searched for generic anchors and replaced them with more explicit names.