Generic type parameters in return types incorrectly split across lines

[portlek]

The formatter incorrectly splits generic type parameters (like Dictionary and Array) across multiple lines, breaking the syntax.

Input:

func test() -> Dictionary[String, String]:
    return {}

Output (broken):

func test() -> Dictionary[
    String,
    String
]:
    return { }

Expected:
The generic type should remain intact as Dictionary[String, String] on a single line.

Reproduction:
gdscript-formatter --max-line-length 10

This also occurs with Array[...] types and without --max-line-length on longer functions.