Syntax Highlighting regex+format strings (rf) #256

• Editor name and version: VSCode 1.75.1
• Platform: macOS
• Color scheme: Dark+ (default)
• MagicPython version: 1.1.0
• A sreenshot:
  
• 5-10 lines of surrounding code:

myString = "baz"
MYCONST = "qux"
myDict = {
    "foo": "bar"
}

correctColoring = rf"(?=[\w]+){myString}{MYCONST}[\d]+"

incorrectDictionary = rf"(?=[\w]+){myDict['foo']}[\d]+"
regularFString = f"word{myDict['foo']}number"

This is a followup to #186. After upgrading to 1.1.0, I'm very excited that rf strings support both regex style and format string. In the attached screenshot, behold how correctly varied correctColoring is. However, any dictionary or class inside of the {} in an rf string is not colored correctly. See how myDict['foo'] varies between incorrectDictionary and regularFString. The square brackets should be purple, and 'foo' orange, but instead it is all absorbed into red.