Support fmt: skip for simple-statements and decorators (#6561)

crates/ruff_python_formatter/src/expression/mod.rs

@@ -94,7 +94,7 @@ impl FormatRule<Expr, PyFormatContext<'_>> for FormatExpr {
             Expr::List(expr) => expr.format().fmt(f),
             Expr::Tuple(expr) => expr.format().fmt(f),
             Expr::Slice(expr) => expr.format().fmt(f),
-            Expr::IpyEscapeCommand(_) => todo!(),
+            Expr::IpyEscapeCommand(expr) => expr.format().fmt(f),
         });
 
         let parenthesize = match parentheses {