afinfo: add page (en, zh) (#3652)

pages/osx/afinfo.md

@@ -0,0 +1,28 @@
+# afinfo
+
+> Audio file metadata parser for OS X.
+> Built-in command of OS X.
+
+- Display info of a given audio file:
+
+`afinfo {{path/to/file}}`
+
+- Print a one line description of the audio file:
+
+`afinfo -b {{path/to/file}}`
+
+- Print metadata info and contents of the audio file's InfoDictionary:
+
+`afinfo -i {{path/to/file}}`
+
+- Print output in xml format:
+
+`afinfo -x {{path/to/file}}`
+
+- Print warnings for the audio file if any:
+
+`afinfo --warnings {{path/to/file}}`
+
+- Display help for full usage:
+
+`afinfo -h`