Add Erg Language Server (#318)

Author: mtshiba

index.html

@@ -961,6 +961,34 @@ <h4>Language servers</h4>
             </ul>
           </td>
         </tr>
+        <tr>
+          <th>Erg</th>
+          <td>
+            <a href="https://github.com/mtshiba">Shunsuke Shibayama</a> and contributors
+          </td>
+          <td class="repo">
+            <a href="https://github.com/erg-lang/erg/tree/main/crates/els">github.com/erg-lang/erg/tree/main/crates/els</a>
+          </td>
+          <td class="success">
+            <span class="glyphicon glyphicon-ok" aria-hidden="true"></span>
+          </td>
+          <td class="success">
+            <span class="glyphicon glyphicon-ok" aria-hidden="true"></span>
+          </td>
+          <td class="success">
+            <span class="glyphicon glyphicon-ok" aria-hidden="true"></span>
+          </td>
+          <td class="success">
+            <span class="glyphicon glyphicon-ok" aria-hidden="true"></span>
+          </td>
+          <td class="success">
+            <span class="glyphicon glyphicon-ok" aria-hidden="true"></span>
+          </td>
+          <td class="success">
+            <span class="glyphicon glyphicon-ok" aria-hidden="true"></span>
+          </td>
+          <td></td>
+        </tr>
         <tr>
           <th>Erlang</th>
           <td>