maint: quote 'like this' or "like this", not `like this'

maint: quote 'like this' or "like this", not `like this'

* doc/coreutils.texi (Formatting the file names):
coreutils now quotes 'like this'.
* man/help2man:
* src/timeout.c (usage): Quote 'like this' in diagnostics.
* HACKING, Makefile.am, NEWS, README, README-hacking, TODO, cfg.mk:
* doc/Makefile.am, doc/coreutils.texi, m4/jm-macros.m4:
* man/Makefile.am, man/help2man, src/Makefile.am, src/copy.h:
* src/extract-magic, src/ls.c, src/pinky.c, src/pr.c, src/sort.c:
* src/split.c, src/timeout.c, src/who.c, tests/dd/skip-seek-past-file:
* tests/pr/pr-tests: Quote 'like this' in commentary.
* cfg.mk (old_NEWS_hash): Update due to changed old NEWS.