fileicon: add page (#5953)

Co-authored-by: CleanMachine1 <78213164+CleanMachine1@users.noreply.github.com>

pages/osx/fileicon.md

@@ -0,0 +1,20 @@
+# fileicon
+
+> A macOS CLI to manage custom file and folder icons.
+> More information: <https://github.com/mklement0/fileicon>.
+
+- Set a custom icon for a specific file or directory:
+
+`fileicon set {{path/to/file_or_directory}} {{path/to/icon.png}}`
+
+- Remove a custom icon from a specific file or directory:
+
+`fileicon rm {{path/to/file_or_directory}}`
+
+- Save the custom icon of a file or directory as a `.icns` file into the current directory:
+
+`fileicon get {{path/to/file_or_directory}}`
+
+- Test if a specific file or directory has a custom icon:
+
+`fileicon test {{path/to/file_or_directory}}`