Reapply "Rename mappedBy to map."

pkg/yaml/lib/model.dart

Index: pkg/yaml/lib/model.dart
diff --git a/pkg/yaml/lib/model.dart b/pkg/yaml/lib/model.dart
index 8c111afe3d2b49bcf482c49a12858163792d9c80..7a609b9e204eafaca7899e22afb921338407a04c 100644
--- a/pkg/yaml/lib/model.dart
+++ b/pkg/yaml/lib/model.dart
@@ -91,7 +91,7 @@ class _SequenceNode extends _Node {
   }
 
   String toString() =>
-      '$tag [${Strings.join(content.mappedBy((e) => '$e'), ', ')}]';
+      '$tag [${Strings.join(content.map((e) => '$e'), ', ')}]';
 
   int get hashCode => super.hashCode ^ _hashCode(content);
 
@@ -150,7 +150,7 @@ class _ScalarNode extends _Node {
       // TODO(nweiz): This could be faster if we used a RegExp to check for
       // special characters and short-circuited if they didn't exist.
 
-      var escapedValue = value.charCodes.mappedBy((c) {
+      var escapedValue = value.charCodes.map((c) {
         switch (c) {
         case _Parser.TAB: return "\\t";
         case _Parser.LF: return "\\n";
@@ -223,7 +223,7 @@ class _MappingNode extends _Node {
 
   String toString() {
     var strContent = content.keys
-        .mappedBy((k) => '${k}: ${content[k]}')
+        .map((k) => '${k}: ${content[k]}')
         .join(', ');
     return '$tag {$strContent}';
   }