The message templates for role changes pointed to the governance guidelines,
but this document is the one that actually describes them.
So this commit changes links to GOVERNANCE.md
to point to COMMUNITY-ROLES.md instead.
In addition, some wording changes were made elsewhere that hopefully make the intended message clearer.
This allows the template messages to retain the semantic line-breaking
that improves the readability of their source code version control diffs,
while at the same time they can be copy-pasted to issues
without the line breaks (which is slightly problematic
because github includes the line breaks
even when rendering content as rich-text prose).
Also, slightly reword a sentence in the "Past owners" section,
to make it more general and cover more cases.
