Fixed a few spelling errors

Corrected some spelling mistakes I happened to notice while reading the help docs.

src/ui/pages/help.html

@@ -249,7 +249,7 @@
 						<span class="option">Option: make text searchable</span>
 						<p>Check this option to insert the text content of the saved page into the self-extracting ZIP
 							file. This makes it possible, for example, to search for pages from the text. Note that if
-							the selected fomrmat is "self-extracting ZIP (universal)", the text content is
+							the selected format is "self-extracting ZIP (universal)", the text content is
 							encoded in UTF-8 but the page is declared in ISO-8859-1.
 						</p>
 					</li>
@@ -758,7 +758,7 @@
 				</ul>
 				<p>Misc.</p>
 				<ul>
-					<li data-options-label="addProofLabel"> <span class="option">Option: add proof od existence</span>
+					<li data-options-label="addProofLabel"> <span class="option">Option: add proof of existence</span>
 						<p>Check this option to create a worldwide proof of the existence of the page you want to save.
 						</p>
 						<ul>
@@ -1342,4 +1342,4 @@
 	<script type="module" src="../bg/ui-help.js"></script>
 </body>
 
-</html>
+</html>