Change icon from folder to input

src/web/html/index.html

@@ -226,7 +226,7 @@
                             <label for="input-text">Input</label>
                             <span class="float-right">
                                 <button type="button" class="btn btn-primary bmd-btn-icon" id="btn-open-file" data-toggle="tooltip" title="Open file as input" onclick="document.getElementById('open-file').click();">
-                                    <i class="material-icons">folder</i>
+                                    <i class="material-icons">input</i>
                                     <input type="file" id="open-file" style="display: none">
                                 </button>
                                 <button type="button" class="btn btn-primary bmd-btn-icon" id="clr-io" data-toggle="tooltip" title="Clear input and output">