#1900 Stricter shebang checking for Lua (fix attached)

[Justin Dailey]

Currently the Lua lexer checks to see if the script starts with "#" to determine if it is a shebang line (and thus colorizes it as a comment).

This update is slightly stricter and makes sure it starts with "#!"

Rationale: I use Scintilla as a commandline-like input for running single Lua commands. Since the input isn't actually a "script" then shebangs don't make sense for it. Inputing #mytable (to print out the length of a table) currently gets determined to be a shebang line.

The attatched file has 2 lines changed.

[Neil Hodgson]

Committed as [90eaa9].