Allow to add quotes into stringLiteral parameters

[supakonoha]

Is your feature request related to a problem? Please describe.
I'm using a custom tag that has a string parameter. If this parameter includes a quote, this is interpreted as final quote for the parameter, although it's escaped. For example:

#tag("value", "this is a \"custom\" parameter")

for the second parameter, LeafLexer parses it as this is a \ instead of this is "custom" parameter

Describe the solution you'd like
I would like to allow quotes inside parameters using escape characters or other option.

[roya1v]

As far as I see when we read a string we do not distinguish between quotes that were and were not escaped.
That's why I looked at escaping them using a different character and create a draft #124 of how it could work escaping it like $\ but it should work with any other character too.
Let me know what you think!

[supakonoha]

Looks nice!!!!! Thanks for this change!!!!

Just a suggestion, I don't know if we could define "$" as constant or add into Character extension like quote?