Make colon escapable

[ursacascadia]

I'm working on a Godot project which uses external function calls. Currently, I'm trying to pass a path to a scene through an EXTERNAL function. Unfortunately, Godot's filesystem uses res:// to denote internal files, and the colon causes the compiler to think it is leaving the execution section for conditional text. The colon is currently not escapeable by using a backslash, and it should be for functionality sake.