Fixing typo

webrtc.html

@@ -5902,7 +5902,7 @@ <h2>Methods</h2>
               and can only be used to change what the media stack is sending or
               receiving within the envelope negotiated by Offer/Answer. The
               attributes in the <code><a>RTCRtpParameters</a></code> dictionary
-              are designed o not enable this, so attributes like
+              are designed to not enable this, so attributes like
               <code>cname</code> that cannot be changed are read-only. Other
               things, like bitrate, are controlled using limits such as
               <code>maxBitrate</code>, where the user agent needs to ensure it