Instead of use 'docs/*.md' in dep5. For clarity and avoiding a wide-
matching wildcard.
+ Remove mention of old files from .reuse/dep5
+ add info to .github/dependabot.yml
+ make scripts/copyright.pl warn on non-matching patterns
Closes#13245
A struct bufref holds a buffer pointer, a data size and a destructor.
When freed or its contents are changed, the previous buffer is implicitly
released by the associated destructor. The data size, although not used
internally, allows binary data support.
A unit test checks its handling methods: test 1661
Closes#6654
