Auto merge of rust-lang#14621 - alibektas:make_impl_trait_fix, r=Veykril

Simple fix for make::impl_trait

This is my first PR in this project. I made this PR because I needed this function to work properly for the main PR I am working on  (rust-lang#14386). This is a small amendment to what it was before. We still need to improve this in order for it to fully comply with its syntactic definition as  stated [here](https://doc.rust-lang.org/reference/items/implementations.html).

Author: bors

crates/syntax/src/ast/make.rs

@@ -184,8 +184,11 @@ pub fn impl_trait(
     ty: ast::Path,
     ty_params: Option<ast::GenericParamList>,
 ) -> ast::Impl {
-    let ty_params = ty_params.map_or_else(String::new, |params| params.to_string());
-    ast_from_text(&format!("impl{ty_params} {trait_} for {ty}{ty_params} {{}}"))
+    // TODO : If this function is now correct we can also change `impl_` accordingly`
+    let ty_params_str = ty_params.as_ref().map_or_else(String::new, |params| params.to_string());
+    let ty_genargs_str =
+        ty_params.map_or_else(String::new, |params| params.to_generic_args().to_string());
+    ast_from_text(&format!("impl{ty_params_str} {trait_} for {ty}{ty_genargs_str} {{}}"))
 }
 
 pub fn path_segment(name_ref: ast::NameRef) -> ast::PathSegment {