Editorial: fix typo (#1824)

protcols -> protocols

index.html

@@ -10460,7 +10460,7 @@ <h3>User Prompt Handler</h3>
 handler, but instead falls back to the "<code>accept</code>" handler
 if no more specific handler is defined. This is because HTTP-only
 sessions do not allow the "<code>beforeUnload</code>" handler to be
-customized, and enabling other protcols isn&apos;t expected to change
+customized, and enabling other protocols isn&apos;t expected to change
 the user prompt handling as a side effect.
 
 <p>To <dfn>deserialize as an unhandled prompt behavior</dfn> given