ide-db: Fix warnings about clippy str_to_string rule

Author: tetsuharuohzeki

crates/ide-db/src/syntax_helpers/format_string_exprs.rs

@@ -203,7 +203,7 @@ mod tests {
     use expect_test::{expect, Expect};
 
     fn check(input: &str, expect: &Expect) {
-        let (output, exprs) = parse_format_exprs(input).unwrap_or(("-".to_string(), vec![]));
+        let (output, exprs) = parse_format_exprs(input).unwrap_or(("-".to_owned(), vec![]));
         let outcome_repr = if !exprs.is_empty() {
             format!("{output}; {}", with_placeholders(exprs).join(", "))
         } else {

crates/ide-db/src/tests/sourcegen_lints.rs

@@ -52,7 +52,7 @@ pub struct LintGroup {
     generate_lint_descriptor(sh, &mut contents);
     contents.push('\n');
 
-    let cargo = std::env::var("CARGO").unwrap_or_else(|_| "cargo".to_string());
+    let cargo = std::env::var("CARGO").unwrap_or_else(|_| "cargo".to_owned());
     let unstable_book = project_root().join("./target/unstable-book-gen");
     cmd!(
         sh,
@@ -283,7 +283,7 @@ fn generate_descriptor_clippy(buf: &mut String, path: &Path) {
             let line = &line[..up_to];
 
             let clippy_lint = clippy_lints.last_mut().expect("clippy lint must already exist");
-            clippy_lint.help = unescape(line).trim().to_string();
+            clippy_lint.help = unescape(line).trim().to_owned();
         }
     }
     clippy_lints.sort_by(|lint, lint2| lint.id.cmp(&lint2.id));