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.rs

@@ -1209,7 +1209,7 @@ mod tests {
             append(&mut buffer, "foo(\n1)", cx);
             assert_eq!(
                 buffer.text(),
-                "def a():\n  \n  if a:\n    b()\n  else:\n    foo(\n      1)"
+                "def a():\n  \n  if a:\n    b()\n  else:\n    foo(\n    1)"
             );
 
             // dedent the closing paren if it is shifted to the beginning of the line
@@ -1255,7 +1255,7 @@ mod tests {
 
             // dedent "else" on the line after a closing paren
             append(&mut buffer, "\n  else:\n", cx);
-            assert_eq!(buffer.text(), "if a:\n  b(\n  )\nelse:\n  ");
+            assert_eq!(buffer.text(), "if a:\n  b(\n  )\nelse:\n");
 
             buffer
         });