add newline after doc comments, add tests for doc comments

Bug: #55128
Change-Id: I6897e33ad291093d460e28a0b0f374d6504418e5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/356260
Auto-Submit: Jake Macdonald <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: jakemac53

pkg/_fe_analyzer_shared/lib/src/macros/executor/builder_impls.dart

@@ -574,7 +574,7 @@ DeclarationCode _buildFunctionAugmentation(
   assert(initializers == null || declaration is ConstructorDeclaration);
 
   return new DeclarationCode.fromParts([
-    if (docComments != null) docComments,
+    if (docComments != null) ...[docComments, '\n'],
     if (declaration is MethodDeclaration) '  ',
     'augment ',
     if (declaration is ConstructorDeclaration) ...[

pkg/_fe_analyzer_shared/test/macros/executor/executor_test.dart

@@ -676,6 +676,7 @@ class LibraryInfo {
                 expect(
                     result.libraryAugmentations.single.debugString().toString(),
                     equalsIgnoringWhitespace('''
+                // A comment!
                 augment String myFunction() {
                   print('isExternal: false');
                   print('isGetter: false');
@@ -733,6 +734,7 @@ class LibraryInfo {
                 expect(
                     result.libraryAugmentations.single.debugString().toString(),
                     equalsIgnoringWhitespace('''
+                // A comment!
                 augment String get myVariable {
                   print('isExternal: false');
                   print('isGetter: true');
@@ -754,6 +756,7 @@ class LibraryInfo {
                 expect(
                     result.libraryAugmentations.single.debugString().toString(),
                     equalsIgnoringWhitespace('''
+                // A comment!
                 augment void set myVariable(String value, ) {
                   print('isExternal: false');
                   print('isGetter: false');
@@ -1020,6 +1023,7 @@ final fieldDefinitionMatchers = [
 
 final methodDefinitionMatchers = [
   equalsIgnoringWhitespace('''
+    // A comment!
     augment (String, bool? hello, {String world}) myMethod() {
       print('definingClass: MyClass');
       print('isExternal: false');
@@ -1050,6 +1054,7 @@ final methodDefinitionMatchers = [
 
 final mixinMethodDefinitionMatchers = [
   equalsIgnoringWhitespace('''
+    // A comment!
     augment (String, bool? hello, {String world}) myMixinMethod() {
       print('definingClass: MyMixin');
       print('isExternal: false');

pkg/_fe_analyzer_shared/test/macros/executor/simple_macro.dart

@@ -323,7 +323,8 @@ class SimpleMacro
   @override
   Future<void> buildDefinitionForFunction(
       FunctionDeclaration function, FunctionDefinitionBuilder builder) async {
-    builder.augment(await _buildFunctionAugmentation(function, builder));
+    builder.augment(await _buildFunctionAugmentation(function, builder),
+        docComments: CommentCode.fromString('// A comment!'));
   }
 
   @override