for-each-ref: reword the documentation for '--start-after'

The documentation for '--start-after' states that the flag cannot be
used with general pattern matching. This is a bit vague, since there is
no clear understanding about what 'general' means here. Rewrite the
sentence to be more specific.

While here, fix a typo in the 'OPT_STRING'.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: KarthikNayak

Documentation/git-for-each-ref.adoc

@@ -114,7 +114,8 @@ TAB %(refname)`.
     deleted, modified or added between invocations. Output will only yield those
     references which follow the marker lexicographically. Output begins from the
     first reference that would come after the marker alphabetically. Cannot be
-    used with general pattern matching or custom sort options.
+    used with `--sort=<key>` or `--stdin` options, or the _<pattern>_ argument(s)
+    to limit the refs.
 
 FIELD NAMES
 -----------

builtin/for-each-ref.c

@@ -45,7 +45,7 @@ int cmd_for_each_ref(int argc,
 		OPT_GROUP(""),
 		OPT_INTEGER( 0 , "count", &format.array_opts.max_count, N_("show only <n> matched refs")),
 		OPT_STRING(  0 , "format", &format.format, N_("format"), N_("format to use for the output")),
-		OPT_STRING(  0 , "start-after", &filter.start_after, N_("start-start"), N_("start iteration after the provided marker")),
+		OPT_STRING(  0 , "start-after", &filter.start_after, N_("start-after"), N_("start iteration after the provided marker")),
 		OPT__COLOR(&format.use_color, N_("respect format colors")),
 		OPT_REF_FILTER_EXCLUDE(&filter),
 		OPT_REF_SORT(&sorting_options),