chmod: remove square brackets around "recursively"

pages/common/chmod.md

@@ -22,6 +22,6 @@
 
 `chmod o=g {{file}}`
 
-- Change permissions [-R]ecursively giving [g]roup and [o]thers the abililty to [w]rite:
+- Change permissions recursively giving [g]roup and [o]thers the abililty to [w]rite:
 
 `chmod -R g+w,o+w {{directory}}`