[Lex] - Assume %if 0 followed by %endif is a comment

[harm-smits]

It is common practice to use %if 0 along with %endif to make block comments in NASM. Do you recon its feasible to add support for this? Wouldn't seem more than adjusting the NASMCommenter.java file:

JetBrains-NASM-Language/src/com/nasmlanguage/NASMCommenter.java

Line 35 in f4c3a8f

public String getBlockCommentPrefix() {

[ajkhoury]

This turns out to be more difficult than originally thought. I think I'm going to have to adjust the language flex to track %if 0 along with %endif blocks since %if is matched as a preprocessor rule in the language BNF.