add test, remove "" skip, fix #210

[krux02]

I would like to point out, that a raw string is not just an r before the string literal, it can be any identifier before a string literal.

My fix isn't 100% correct. It treats r" abc""def " like two different literals, but for syntax highlighting, that doesn't matter at all.

[yuutayamada]

It matters. As far as I remember it's for evil (vi emulation) command like di" (delete inside ""). It works based on emacs' syntax class (https://www.gnu.org/software/emacs/manual/html_node/elisp/Syntax-Class-Table.html)

[krux02]

I guess you have to make a decision here:

Either:

• If the user uses evil mode, and he wants to change something inside a string literal, and he uses the i" command for it, and the string literal is a raw string literal, and the raw string literal contains escaped double quotes, three more keystrokes are needed.

Or:

• Have a corner case where half of a file from the compiler isn't highlighted at all (more than 300 lines), and of course vi commands such as di" won't work properly either.

Of course you can also provide a better solution.

[yuutayamada]

Have a corner case where half of a file from the compiler isn't highlighted at all (more than 300 lines), and of course vi commands such as di" won't work properly either.

I think I can fix for the raw string literal

[yuutayamada]

closing this PR because #210 was fixed