language: Fix indent suggestions for significant indented languages like Python (#29625)

Closes #26157

This fixes multiple cases where Python indentation breaks:
- [x] Adding a new line after `if`, `try`, etc. correctly indents in
that scope
- [x] Multi-cursor tabs correctly preserve relative indents
- [x] Adding a new line after `else`, `finally`, etc. correctly outdents
them
- [x] Existing Tests

Future Todo: I need to add new tests for all the above cases.

Before/After:

1. Multi-cursor tabs correctly preserve relative indents


https://github.com/user-attachments/assets/08a46ddf-5371-4e26-ae7d-f8aa0b31c4a2

2. Adding a new line after `if`, `try`, etc. correctly indents in that
scope


https://github.com/user-attachments/assets/9affae97-1a50-43c9-9e9f-c1ea3a747813

Release Notes:

- Fixes indentation-related issues involving tab, newline, etc for
Python.

crates/languages/src/python/config.toml

@@ -27,6 +27,7 @@ brackets = [
 ]
 
 auto_indent_using_last_non_empty_line = false
-increase_indent_pattern = "^[^#].*:\\s*$"
-decrease_indent_pattern = "^\\s*(else|elif|except|finally)\\b.*:"
 debuggers = ["Debugpy"]
+significant_indentation = true
+increase_indent_pattern = "^\\s*(try)\\b.*:"
+decrease_indent_pattern = "^\\s*(else|elif|except|finally)\\b.*:"