Merge branch 'ab/doc-lint'

Dev support. * ab/doc-lint: docs: fix linting issues due to incorrect relative section order doc lint: lint relative section order doc lint: lint and fix missing "GIT" end sections doc lint: fix bugs in, simplify and improve lint script doc lint: Perl "strict" and "warnings" in lint-gitlink.perl Documentation/Makefile: make doc.dep dependencies a variable again Documentation/Makefile: make $(wildcard howto/*.txt) a var