feat: vuejs#1371 Append the file extension to the mapping files in devtools

Author: YuJianrong

Diff for: lib/select.js

@@ -1,6 +1,7 @@
 module.exports = function selectBlock (descriptor, loaderContext, query) {
   // template
   if (query.type === `template`) {
+    loaderContext.resourcePath += '.' + (descriptor.template.type || 'template')
     loaderContext.callback(
       null,
       descriptor.template.content,
@@ -11,6 +12,7 @@ module.exports = function selectBlock (descriptor, loaderContext, query) {
 
   // script
   if (query.type === `script`) {
+    loaderContext.resourcePath += '.' + (descriptor.script.lang || 'js')
     loaderContext.callback(
       null,
       descriptor.script.content,
@@ -22,6 +24,7 @@ module.exports = function selectBlock (descriptor, loaderContext, query) {
   // styles
   if (query.type === `style` && query.index != null) {
     const style = descriptor.styles[query.index]
+    loaderContext.resourcePath += '.' + (style.lang || 'css')
     loaderContext.callback(
       null,
       style.content,