Fix numerical syntax

[erw7]

• Fix problem that integer suffix was not highlighted, Because the numeric part matches the floating point pattern defined later(Comment unrecognized inline with integer type declaration #41, syntax highlighting doesn't detect int literals #48).
• Supports binary, octal syntax highlight.
• It corresponds to suffix(u, d, f128 etc) which did not correspond.
• Fix highlighted invalid number that beginning is underscore or includes consecutive underscore.
• Fix problem highlighted invalid floating point suffix like 'f8.
• Change to parentheses that don't capturing groups.

[zah]

Thanks for making all these pull-requests. I'll soon merge the nimsuggest-related changes as well.