Support generic function in generate_function assist

crates/syntax/src/ast/make.rs

@@ -823,6 +823,7 @@ pub fn fn_(
     visibility: Option<ast::Visibility>,
     fn_name: ast::Name,
     type_params: Option<ast::GenericParamList>,
+    where_clause: Option<ast::WhereClause>,
     params: ast::ParamList,
     body: ast::BlockExpr,
     ret_type: Option<ast::RetType>,
@@ -832,6 +833,10 @@ pub fn fn_(
         Some(type_params) => format!("{type_params}"),
         None => "".into(),
     };
+    let where_clause = match where_clause {
+        Some(it) => format!("{it} "),
+        None => "".into(),
+    };
     let ret_type = match ret_type {
         Some(ret_type) => format!("{ret_type} "),
         None => "".into(),
@@ -844,7 +849,7 @@ pub fn fn_(
     let async_literal = if is_async { "async " } else { "" };
 
     ast_from_text(&format!(
-        "{visibility}{async_literal}fn {fn_name}{type_params}{params} {ret_type}{body}",
+        "{visibility}{async_literal}fn {fn_name}{type_params}{params} {ret_type}{where_clause}{body}",
     ))
 }