Syntax Highlighting for custom type hints fails after linebreaks in parameter list

### Tested versions

4.2.1

### System information

Windows 10, Godot 4.2.1, Gles3 compatibility

### Issue description

When adding typehints to function declarations the highlighting stops working if linebreaks are added:


### Steps to reproduce

Write a function with type hints for some custom types. Add linebreaks in the parameter list

### Minimal reproduction project (MRP)

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Reproduce the issue using the listed steps in Godot 4.2.1: add custom type hints to a function declaration, then insert line breaks in its parameter list. Trace the editor's syntax-highlighting behavior for this case and verify that highlighting continues correctly across the line breaks.

Written by the indexing model from the issue text.