Incorrect suffix highlighting for numeric literals in C-like languages

[yanchith]

Describe the bug

Set language to C and type in literal 1l. The "l" is not highlit. (If you type 10l, it is highlit)

This is because the C tokenizer doesn't attempt to parse suffixes unless there's more than one number-or-decimal-point in the input.

I discovered this when making syntax highlighting for my own editor (using Focus as a reference). I am happy to send a pull request.