fix lint

diff --git a/pkgs/markdown/analysis_options.yaml b/pkgs/markdown/analysis_options.yaml
index 0eb0eaa..5d0d0c2 100644
--- a/pkgs/markdown/analysis_options.yaml
+++ b/pkgs/markdown/analysis_options.yaml

@@ -51,7 +51,7 @@
     #- type_annotate_public_apis
     - type_init_formals
     #- unawaited_futures
-    - unnecessary_brace_in_string_interp
+    - unnecessary_brace_in_string_interps
     #- unnecessary_getters_setters
     - unrelated_type_equality_checks
     - valid_regexps

diff --git a/pkgs/markdown/tool/dartdoc-compare.dart b/pkgs/markdown/tool/dartdoc-compare.dart
index ca8ea30..ad7827c 100644
--- a/pkgs/markdown/tool/dartdoc-compare.dart
+++ b/pkgs/markdown/tool/dartdoc-compare.dart

@@ -63,14 +63,14 @@
     var diffOptions = ["-r", "-B", out_before, out_after];
     var result = Process.runSync("diff", diffOptions, runInShell: true);
     var nlines = "\n".allMatches(result.stdout).length;
-    print("Diff lines: ${ nlines }");
+    print("Diff lines: $nlines");
     print("diff ${diffOptions.join(" ")}");
     return result.exitCode == 0;
   }
 
   String run_dartdoc(markdown_ref, package) {
     print("==========================================================");
-    print("Running dartdoc for ${markdown_ref}...");
+    print("Running dartdoc for $markdown_ref...");
     print("==========================================================");
     doInPath(dartdoc_dir, () => update_dartdoc_pubspec(markdown_ref));
     return doInPath(package, () {
@@ -80,7 +80,7 @@
       var sdk_options =
           sdk ? ["--sdk-docs", "--dart-sdk=$package"] : <String>[];
       var cmd = "dart";
-      var args = ["${dartdoc_bin}", "--output=${out.path}"]
+      var args = ["$dartdoc_bin", "--output=${out.path}"]
         ..addAll(sdk_options);
       print("Command: $cmd ${args.join(" ")}");
       system(cmd, args);

diff --git a/pkgs/markdown/tool/stats.dart b/pkgs/markdown/tool/stats.dart
index a9c00c3..20ebd1e 100644
--- a/pkgs/markdown/tool/stats.dart
+++ b/pkgs/markdown/tool/stats.dart

@@ -228,14 +228,14 @@
 
     sink.writeln('${sectionValidCount.toString().padLeft(countWidth)} '
         'of ${total.toString().padLeft(countWidth)} '
-        '– ${pct}%  $section');
+        '– $pct%  $section');
   });
 
   var pct = (100 * totalValid / totalExamples).toStringAsFixed(1).padLeft(5);
 
   sink.writeln('${totalValid.toString().padLeft(countWidth)} '
       'of ${totalExamples.toString().padLeft(countWidth)} '
-      '– ${pct}%  TOTAL');
+      '– $pct%  TOTAL');
 
   await sink.flush();
   await sink.close();