* 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