QuickEdit will highlight your text according to syntax parsing result.
The syntax language is determined automatically from the file extension. For instance, "Main.java" will use Java language automatically.
Currently QuickEdit support following languages:
Change Syntax Language
If QuickEdit cannot find the correct language for your text file, you can force it to change to the language schema that you need.
You can do this by clicking More->Syntax from action bar. It will launch language list dialog for you to choose. "Automatic" means to determine the language according to file extension.