Fix typo in web UI copy (#394)

code/html/index.html

@@ -341,10 +341,10 @@
                                 <div class="pure-g module module-multirelay">
                                     <label class="pure-u-1 pure-u-lg-1-4">Switch sync mode</label>
                                     <select name="relaySync" class="pure-u-1 pure-u-lg-3-4" tabindex="3">
-                                        <option value="0">No synchonisation</option>
+                                        <option value="0">No synchronisation</option>
                                         <option value="1">Zero or one switches active</option>
                                         <option value="2">One and just one switch active</option>
-                                        <option value="3">All synchonised</option>
+                                        <option value="3">All synchronised</option>
                                     </select>
                                     <div class="pure-u-0 pure-u-lg-1-4"></div>
                                     <div class="pure-u-1 pure-u-lg-3-4 hint">Define how the different switches should be synchronized.</div>