[web] Fix undesired scrollbars on shell files (#4104)

src/minshell.html

@@ -34,7 +34,11 @@
     <link rel="shortcut icon" href="https://www.raylib.com/favicon.ico">
 
     <style>
-        body { margin: 0px; }
+        body { 
+          margin: 0px; 
+          overflow: hidden; 
+          background-color: black;
+        }
         canvas.emscripten { border: 0px none; background-color: black;}
     </style>
     <script type='text/javascript' src="https://cdn.jsdelivr.net/gh/eligrey/FileSaver.js/dist/FileSaver.min.js"> </script>

src/shell.html

@@ -141,6 +141,11 @@ jwE50AGjLCVuS8Yt4H7OgZLKK5EKOsLviEWJSL/+0uMi7gLUSBseYwqEbXvSHCec1CJvZPyHCmYQffaB
       }
 
       #output {
+        border-left: 0px none;
+        border-right: 0px none;
+        border-bottom: 0px none;
+        padding-left: 0;
+        padding-right: 0;
         width: 100%;
         height: 140px;
         margin: 0 auto;