Fixes missing field descriptions if the Message has index 2

Author: t-yuki

examples/examplepb/streamless_everything.proto

@@ -59,6 +59,7 @@ message EmptyMessage {
 }
 
 message IdMessage {
+	// uuid is UUID value
 	string uuid = 1;
 }
 

examples/examplepb/streamless_everything.swagger.json

@@ -520,7 +520,8 @@
       "properties": {
         "uuid": {
           "type": "string",
-          "format": "string"
+          "format": "string",
+          "title": "uuid is UUID value"
         }
       }
     },

protoc-gen-swagger/genswagger/template.go

@@ -564,7 +564,7 @@ func protoComments(reg *descriptor.Registry, file *descriptor.File, outers []str
 	packageProtoPath := protoPathIndex(reflect.TypeOf((*pbdescriptor.FileDescriptorProto)(nil)), "Package")
 L1:
 	for _, loc := range file.SourceCodeInfo.Location {
-		if typeIndex != packageProtoPath {
+		if typeName != "Package" || typeIndex != packageProtoPath {
 			if len(loc.Path) < len(outerPaths)*2+2+len(fieldPaths) {
 				continue
 			}