Address review comments

Author: smoelius

clippy_dev/src/new_lint.rs

@@ -255,9 +255,9 @@ fn get_lint_file_contents(lint: &LintData<'_>, enable_msrv: bool) -> String {
     let name_camel = to_camel_case(lint.name);
     let name_upper = lint_name.to_uppercase();
 
-    #[expect(clippy::format_push_string)]
-    result.push_str(&if enable_msrv {
-        formatdoc!(
+    if enable_msrv {
+        let _: fmt::Result = writedoc!(
+            result,
             r"
             use clippy_utils::msrvs::{{self, Msrv}};
             use clippy_config::Conf;
@@ -266,23 +266,24 @@ fn get_lint_file_contents(lint: &LintData<'_>, enable_msrv: bool) -> String {
             use rustc_session::impl_lint_pass;
 
         "
-        )
+        );
     } else {
-        formatdoc!(
+        let _: fmt::Result = writedoc!(
+            result,
             r"
             {pass_import}
             use rustc_lint::{{{context_import}, {pass_type}}};
             use rustc_session::declare_lint_pass;
 
         "
-        )
-    });
+        );
+    }
 
     let _: fmt::Result = writeln!(result, "{}", get_lint_declaration(&name_upper, category));
 
-    #[expect(clippy::format_push_string)]
-    result.push_str(&if enable_msrv {
-        formatdoc!(
+    if enable_msrv {
+        let _: fmt::Result = writedoc!(
+            result,
             r"
             pub struct {name_camel} {{
                 msrv: Msrv,
@@ -303,16 +304,17 @@ fn get_lint_file_contents(lint: &LintData<'_>, enable_msrv: bool) -> String {
             // TODO: Add MSRV level to `clippy_config/src/msrvs.rs` if needed.
             // TODO: Update msrv config comment in `clippy_config/src/conf.rs`
         "
-        )
+        );
     } else {
-        formatdoc!(
+        let _: fmt::Result = writedoc!(
+            result,
             r"
             declare_lint_pass!({name_camel} => [{name_upper}]);
 
             impl {pass_type}{pass_lifetimes} for {name_camel} {{}}
         "
-        )
-    });
+        );
+    }
 
     result
 }

clippy_lints/src/format_push_string.rs

@@ -11,7 +11,7 @@ declare_clippy_lint! {
     /// Detects cases where the result of a `format!` call is
     /// appended to an existing `String`.
     ///
-    /// ### Why restrict this?
+    /// ### Why is this bad?
     /// Introduces an extra, avoidable heap allocation.
     ///
     /// ### Known problems