Fix README.md for sst command

plugins/sublime/README.md

@@ -14,4 +14,6 @@ Plugin for Sublime Text, a cross platform text and code editor, available for Li
 
  * If `st` is passed a file, open it in Sublime Text
 
- * if `stt` command is called, it is equivalent to `st .`, opening the current folder in Sublime Text
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+ * If `stt` command is called, it is equivalent to `st .`, opening the current folder in Sublime Text
+ 
+ * If `sst` command is called, it is like `sudo st`, opening the file or folder in Sublime Text. Useful for editing system protected files.
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