Trivial nit fixes (#12285)

diff --git a/packages/flutter_tools/lib/src/devfs.dart b/packages/flutter_tools/lib/src/devfs.dart
index 938d5de..65a5b71 100644
--- a/packages/flutter_tools/lib/src/devfs.dart
+++ b/packages/flutter_tools/lib/src/devfs.dart
@@ -30,7 +30,7 @@
 abstract class DevFSContent {
   bool _exists = true;
 
-  /// Return `true` if this is the first time this method is called
+  /// Return true if this is the first time this method is called
   /// or if the entry has been modified since this method was last called.
   bool get isModified;
 
@@ -125,7 +125,7 @@
     _isModified = true;
   }
 
-  /// Return `true` only once so that the content is written to the device only once.
+  /// Return true only once so that the content is written to the device only once.
   @override
   bool get isModified {
     final bool modified = _isModified;