tag: add page (#15124)

Co-authored-by: Wiktor Perskawiec <git@spageektti.cc>
Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

pages/osx/tag.md

@@ -0,0 +1,20 @@
+# tag
+
+> Edit tags on Mac OS X files (10.9 Mavericks and above).
+> More information: <https://github.com/jdberry/tag/>.
+
+- Add tags to a file:
+
+`tag --add {{tag_name1,tag_name2,...}} {{path/to/file}}`
+
+- Remove a tag:
+
+`tag --remove {{tag_name}} {{path/to/file}`
+
+- Remove all tags from a file:
+
+`tag --remove \* {{path/to/file}}`
+
+- Show all files with a given tag:
+
+`tag --match {{tag_name}}`