fix: update edit button demo

Author: QingWei-Li

docs/de-de/write-a-plugin.md

@@ -79,7 +79,7 @@ window.$docsify = {
   plugins: [
     function(hook, vm) {
       hook.beforeEach(function (html) {
-        var url = 'https://github.com/QingWei-Li/docsify/blob/master' + vm.router.getFile()
+        var url = 'https://github.com/QingWei-Li/docsify/blob/master/docs' + vm.router.getFile()
         var editHtml = '[📝 EDIT DOCUMENT](' + url + ')\n'
 
         return editHtml

docs/index.html

@@ -53,7 +53,7 @@
     plugins: [
       function(hook, vm) {
         hook.beforeEach(function (html) {
-          var url = 'https://github.com/QingWei-Li/docsify/blob/master' + vm.router.getFile()
+          var url = 'https://github.com/QingWei-Li/docsify/blob/master/docs' + vm.router.getFile()
           var editHtml = '[📝 EDIT DOCUMENT](' + url + ')\n'
 
           return editHtml

docs/write-a-plugin.md

@@ -78,7 +78,7 @@ window.$docsify = {
   plugins: [
     function(hook, vm) {
       hook.beforeEach(function (html) {
-        var url = 'https://github.com/QingWei-Li/docsify/blob/master' + vm.router.getFile()
+        var url = 'https://github.com/QingWei-Li/docsify/blob/master/docs' + vm.router.getFile()
         var editHtml = '[📝 EDIT DOCUMENT](' + url + ')\n'
 
         return editHtml

docs/zh-cn/write-a-plugin.md

@@ -79,7 +79,7 @@ window.$docsify = {
   plugins: [
     function(hook, vm) {
       hook.beforeEach(function (html) {
-        var url = 'https://github.com/QingWei-Li/docsify/blob/master' + vm.router.getFile()
+        var url = 'https://github.com/QingWei-Li/docsify/blob/master/docs' + vm.router.getFile()
         var editHtml = '[📝 EDIT DOCUMENT](' + url + ')\n'
 
         return editHtml