Unexpected Swift syntax highlighting when using raw string

### Describe the bug
When using raw string to represent double quote (#"""#) in .swift file, syntax highlighting can't detect the end of the string and will highlight all of the code below as a string.

### Version & OS
macOS Big Sur 11.5.1
GitHub Desktop 2.9.0 (x64)

### Steps to reproduce the behavior
1. Create a .swift file
2. Create a raw string #"""#
3. Add some code after raw string
3. See unexpected syntax highlighting in GitHub Desktop

### Expected behavior
Proper syntax highlighting

### Actual behavior
Unexpected syntax highlighting