Add additional pre-commit hooks (#245)

* Add and run end-of-file-fixer
* Add and run trailing-whitespace
* Add and run check-yaml
* Add and run check-json
* Add and run pretty-format-yaml
* Fix comment indentation

pyscriptjs/examples/panel_kmeans.html

@@ -26,7 +26,7 @@
     <script type="text/javascript">
       Bokeh.set_log_level("info");
     </script>
-        
+
     <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.6.1/dist/css/bootstrap.min.css">
     <link rel="stylesheet" href="https://unpkg.com/@holoviz/panel@0.13.0/dist/bundled/bootstraptemplate/bootstrap.css">
     <link rel="stylesheet" href="https://unpkg.com/@holoviz/panel@0.13.0/dist/bundled/defaulttheme/default.css">
@@ -43,7 +43,7 @@
     <link rel="stylesheet" href="../build/pyscript.css" />
     <script defer src="../build/pyscript.js"></script>
   </head>
-  
+
   <py-env>
     - altair
     - numpy