fix: rename exclude resource definitions flag

Aligns with aip-go.

README.md

@@ -40,9 +40,9 @@ insertion_point         If non-empty, indicates that the named file should alrea
                         and the content here is to be inserted into that file at a defined 
                         insertion point. 
 
-skip_file_resource_definitions
+exclude_resource_definitions
                         If set to true, resource names will not be generated for resource definitions
-                        in the file scope. Default: false.
+                        in the file scope, only on messages. Default: false.
 ```
 
 ---

internal/plugin/generate.go

@@ -42,7 +42,7 @@ func Generate(request *pluginpb.CodeGeneratorRequest) (*pluginpb.CodeGeneratorRe
 		if _, ok := generate[descriptor.ParentFile]; !ok {
 			return true
 		}
-		if opts.SkipFileResourceDefinitions && !isMessageResourceDescriptor(descriptor) {
+		if opts.ExcludeResourceDefinitions && !isMessageResourceDescriptor(descriptor) {
 			return true
 		}
 		dir := path.Dir(descriptor.ParentFile)

internal/plugin/options.go

@@ -15,10 +15,10 @@ type Options struct {
 	// Defaults to `""` (ie. no insertion point)
 	InsertionPoint string
 
-	// SkipFileResourceDefinitions disables generation of resource names
-	// declared in the file scope.
+	// ExcludeResourceDefinitions disables generation of resource names
+	// based on resource definitions in the file.
 	// Defaults to false.
-	SkipFileResourceDefinitions bool
+	ExcludeResourceDefinitions bool
 }
 
 func defaultOptions() Options {
@@ -51,12 +51,12 @@ func (o *Options) Unmarshal(s *string) error {
 			o.InsertionPoint = value
 		case "filename":
 			o.Filename = value
-		case "skip_file_resource_definitions":
+		case "":
 			b, err := unmarshalBool(value)
 			if err != nil {
-				return fmt.Errorf("unmarshal skip_file_resource_definitions: %w", err)
+				return fmt.Errorf("unmarshal exclude_resource_definitions: %w", err)
 			}
-			o.SkipFileResourceDefinitions = b
+			o.ExcludeResourceDefinitions = b
 		default:
 			return fmt.Errorf("unknown option [%s]", opt)
 		}