Fix typo for "specficiations" in Sessions section (#1822)

Author: katranci

index.html

@@ -2240,7 +2240,7 @@ <h2>Sessions</h2>
 flags</dfn> are provided that define the features of the session. This
 specification always creates sessions with "<code>http</code>"
 in <a>session configuration flags</a>, which corresponds to
-the <a>HTTP flag</a>. External specficiations may define additional
+the <a>HTTP flag</a>. External specifications may define additional
 flags, or create sessions without the <a>HTTP flag</a>.
 
 <h3>Global State</h3>