Fix StmtAnnAssign formatting by mirroring StmtAssign (#5732)

## Summary

`StmtAnnAssign` would not insert parentheses when breaking the same way
`StmtAssign` does, causing unstable formatting and likely some syntax
errors.

## Test Plan

I added a regression test.

crates/ruff_python_formatter/src/statement/stmt_ann_assign.rs

@@ -1,3 +1,5 @@
+use crate::expression::maybe_parenthesize_expression;
+use crate::expression::parentheses::Parenthesize;
 use crate::prelude::*;
 use crate::FormatNodeRule;
 use ruff_formatter::write;
@@ -18,11 +20,24 @@ impl FormatNodeRule<StmtAnnAssign> for FormatStmtAnnAssign {
 
         write!(
             f,
-            [target.format(), text(":"), space(), annotation.format()]
+            [
+                target.format(),
+                text(":"),
+                space(),
+                maybe_parenthesize_expression(annotation, item, Parenthesize::IfBreaks)
+            ]
         )?;
 
         if let Some(value) = value {
-            write!(f, [space(), text("="), space(), value.format()])?;
+            write!(
+                f,
+                [
+                    space(),
+                    text("="),
+                    space(),
+                    maybe_parenthesize_expression(value, item, Parenthesize::IfBreaks)
+                ]
+            )?;
         }
 
         Ok(())