status: document options to show matching ignored files

Signed-off-by: Jameson Miller <jamill@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/technical/api-directory-listing.txt

@@ -22,16 +22,20 @@ The notable options are:
 
 `flags`::
 
-	A bit-field of options (the `*IGNORED*` flags are mutually exclusive):
+	A bit-field of options:
 
 `DIR_SHOW_IGNORED`:::
 
-	Return just ignored files in `entries[]`, not untracked files.
+	Return just ignored files in `entries[]`, not untracked
+	files. This flag is mutually exclusive with
+	`DIR_SHOW_IGNORED_TOO`.
 
 `DIR_SHOW_IGNORED_TOO`:::
 
-	Similar to `DIR_SHOW_IGNORED`, but return ignored files in `ignored[]`
-	in addition to untracked files in `entries[]`.
+	Similar to `DIR_SHOW_IGNORED`, but return ignored files in
+	`ignored[]` in addition to untracked files in
+	`entries[]`. This flag is mutually exclusive with
+	`DIR_SHOW_IGNORED`.
 
 `DIR_KEEP_UNTRACKED_CONTENTS`:::
 
@@ -39,6 +43,21 @@ The notable options are:
 	untracked contents of untracked directories are also returned in
 	`entries[]`.
 
+`DIR_SHOW_IGNORED_TOO_MODE_MATCHING`:::
+
+	Only has meaning if `DIR_SHOW_IGNORED_TOO` is also set; if
+	this is set, returns ignored files and directories that match
+	an exclude pattern. If a directory matches an exclude pattern,
+	then the directory is returned and the contained paths are
+	not. A directory that does not match an exclude pattern will
+	not be returned even if all of its contents are ignored. In
+	this case, the contents are returned as individual entries.
++
+If this is set, files and directories that explicity match an ignore
+pattern are reported. Implicity ignored directories (directories that
+do not match an ignore pattern, but whose contents are all ignored)
+are not reported, instead all of the contents are reported.
+
 `DIR_COLLECT_IGNORED`:::
 
 	Special mode for git-add. Return ignored files in `ignored[]` and