fix: formatting for loop (#6807)

## Description
Fix #6804

## Checklist

- [x] I have linked to any relevant issues.
- [ ] I have commented my code, particularly in hard-to-understand
areas.
- [ ] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [ ] If my change requires substantial documentation changes, I have
[requested support from the DevRel
team](https://github.com/FuelLabs/devrel-requests/issues/new/choose)
- [x] I have added tests that prove my fix is effective or that my
feature works.
- [ ] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [ ] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [ ] I have requested a review from the relevant team or maintainers.

Co-authored-by: IGI-111 <[email protected]>

swayfmt/src/utils/language/expr/mod.rs

@@ -279,7 +279,7 @@ impl Format for Expr {
                     |formatter| -> Result<(), FormatterError> {
                         write!(formatted_code, "{} ", ForToken::AS_STR)?;
                         value_pattern.format(formatted_code, formatter)?;
-                        write!(formatted_code, "{} ", InToken::AS_STR)?;
+                        write!(formatted_code, " {} ", InToken::AS_STR)?;
                         iterator.format(formatted_code, formatter)?;
                         IfExpr::open_curly_brace(formatted_code, formatter)?;
                         block.get().format(formatted_code, formatter)?;

swayfmt/src/utils/language/expr/tests.rs

@@ -264,3 +264,13 @@ intermediate_whitespace
 "{
 let i = 42;
 }");
+
+fmt_test_expr!(basic_for_loop
+"for iter in [0, 1, 7, 8, 15] {
+    let i = 42;
+}",
+intermediate_whitespace
+"for iter in [0, 1, 7, 8, 15]{
+let i = 42;
+}"
+);

swayfmt/tests/mod.rs

@@ -3449,3 +3449,43 @@ fn tuple_field_access() {
         "#},
     );
 }
+
+#[test]
+fn contract_for_loop() {
+    check(
+        indoc! {r#"
+        contract;
+
+        abi MyContract {
+            fn test_function() -> bool;
+        }
+
+        impl MyContract for Contract {
+            fn test_function() -> bool {
+                let mut my_vec: Vec<u64> = Vec::new();
+                for iter in my_vec.iter() {
+
+                }
+
+                true
+            }
+        }
+        "#},
+        indoc! {r#"
+        contract;
+
+        abi MyContract {
+            fn test_function() -> bool;
+        }
+
+        impl MyContract for Contract {
+            fn test_function() -> bool {
+                let mut my_vec: Vec<u64> = Vec::new();
+                for iter in my_vec.iter() {    }
+
+                true
+            }
+        }
+        "#},
+    );
+}