DOC: assorted typo fixes in the documentation and Makefile

This is another round of cleanups in various docs and comments in the
Makefile.

(cherry picked from commit 2a950d02a951715447d4068ec6689a842d452aaa)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 99ac71d7fff3cc11d70fb2de2758daf69cd85e42)
[wt: drop changes not for 2.0]
Signed-off-by: Willy Tarreau <w@1wt.eu>
8 files changed