conversion of rest lexer to the modern style.

[mcepl]

Complete don’t understand how to do M._fold function.

[mcepl]

@orbitalquark I think this should be ready for merge.

[orbitalquark]

Thanks, I'll take a look when I have some time.

[orbitalquark]

Once again, thanks for helping out with this. I've committed these changes in https://github.com/orbitalquark/scintillua/commit/064945527e6871fd0cbec5a9ee4b71f22ea7d635 with changes in formatting and the following:

• Moved lex:add_style() calls to be closer to their token definitions.
• Use style property tables in lex:add_style() calls.
• Consolidated lex:add_rule() calls to match convention of modern lexers.
• Updated lexer.word_match() calls to match convention of modern lexers.
• Changed lex.fold() to lex:fold() in order to fix bug in folding.

[mcepl]

Thank you for clean up!