parser: Fix warnings about clippy str_to_string rule

Author: tetsuharuohzeki

crates/parser/src/lexed_str.rs

@@ -149,7 +149,7 @@ impl<'a> Converter<'a> {
 
         if let Some(err) = err {
             let token = self.res.len() as u32;
-            let msg = err.to_string();
+            let msg = err.to_owned();
             self.res.error.push(LexError { msg, token });
         }
     }

crates/parser/src/tests/sourcegen_inline_tests.rs

@@ -60,9 +60,9 @@ fn collect_tests(s: &str) -> Vec<Test> {
     for comment_block in sourcegen::CommentBlock::extract_untagged(s) {
         let first_line = &comment_block.contents[0];
         let (name, ok) = if let Some(name) = first_line.strip_prefix("test ") {
-            (name.to_string(), true)
+            (name.to_owned(), true)
         } else if let Some(name) = first_line.strip_prefix("test_err ") {
-            (name.to_string(), false)
+            (name.to_owned(), false)
         } else {
             continue;
         };