doc: fix some typos, grammar and wording issues

Signed-off-by: Štěpán Němec <stepnem@smrk.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/fsmonitor--daemon.h b/fsmonitor--daemon.h
index 70d776c..673f80d 100644
--- a/fsmonitor--daemon.h
+++ b/fsmonitor--daemon.h
@@ -99,7 +99,7 @@ struct fsmonitor_daemon_state {
  * to only mean an external GITDIR referenced by a ".git" file.
  *
  * The platform FS event backends will receive watch-specific
- * relative paths (except for those OS's that always emit absolute
+ * relative paths (except for those OSes that always emit absolute
  * paths).  We use the following enum and routines to classify each
  * path so that we know how to handle it.  There is a slight asymmetry
  * here because ".git/" is inside the working directory and the