Can't toggle comments in Lua

[ThaisRobba]

This is a pesky bug.

1. Open any .lua file
2. Type anything (can be a simple local a = 10)
3. Try to comment it out using the Ctrl+/ shortcut
4. Nothing happens

Tested under OS X Yosemite, Ubuntu 14.10 and Arch Linux (latest), on three different machines.

[sbruchmann]

Here’s the stack trace:

Uncaught SyntaxError: Invalid regular expression: /^\s*\-\-($|[^\[]|[[^\[]|[$)/:
    Unterminated character class    EditorCommandHandlers.js:70
    _createSpecialLineExp           EditorCommandHandlers.js:70  
    (anonymous function)            EditorCommandHandlers.js:89
    _createLineExpressions          EditorCommandHandlers.js:84
    _getLineCommentPrefix           EditorCommandHandlers.js:190
    (anonymous function)            EditEditorCommandHandlers.js:592
    St                              lodash.js:23
    _getLineCommentEdits            EditorCommandHandlers.js:584
    lineComment                     EditorCommandHandlers.js:616
    Command.execute                 CommandManager.js:97
    execute                         CommandManager.js:291
    executeCommand                  ShellAPI.js:66

[rroshan1]

Verified the fix with the latest branch.