mention --all on fsck man page, and repurpose todo

doc/git-annex-fsck.mdwn

@@ -110,6 +110,13 @@ better format.
   Messages that would normally be output to standard error are included in
   the json instead.
 
+* `--quiet`
+
+  Like all git-annex commands, this option makes only error and warning
+  messages be displayed. This is particularly useful with fsck, which
+  normally displays all the files it's checking even when there is no
+  problem with them.
+
 # SEE ALSO
 
 [[git-annex]](1)

doc/todo/fsck_option_to_only_show_broken.mdwn

@@ -1,3 +1,5 @@
 `git annex fsck` currently spams the terminal with all keys in a repo and prints `git-annex: fsck: n failed` at the end if errors occur. Finding these errors in a sea of `ok`s is not trivial however.
 
 A simple solution to this could be an fsck option which skips printing ok'd (and perhaps also dead) keys, i.e. `--no-ok` and `--no-dead`.
+
+[[!meta title="mention common options on per-command man pages"]]

doc/todo/fsck_option_to_only_show_broken/comment_3_77600b5ce57004e66f9fde7ac8386928._comment

@@ -0,0 +1,15 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 3"""
+ date="2021-05-10T15:07:06Z"
+ content="""
+Normally the common options are not included in every command's man page
+because there are over 100 lines of them. However, I do think it's worth
+including --quiet on fsck's man page in this specific case and am doing
+that.
+
+Maybe individual command man pages should mention that there are
+also a bunch of common options. Perhaps those should be split out of the
+git-annex man page, like the git-annex-matching-options man page is
+handled.
+"""]]