[css-animations] Fix keyword typo

Author: Sylvain Galineau

css-animations/Overview.bs

@@ -991,7 +991,7 @@ The <code>deleteRule</code> method</h4>
 		<dt><dfn argument for="CSSKeyFramesRule/deleteRule()">key</dfn> of type <a interface>DOMString</a>
 		<dd>
 			The key which describes the rule to be deleted. A percentage value between 
-            0% and 100%, or one of the keywords ''fro'' or ''to'' which resolve to 0% and 
+            0% and 100%, or one of the keywords ''from'' or ''to'' which resolve to 0% and 
             100%, respectively.
 	</dl>
 

css-animations/Overview.html

@@ -1006,7 +1006,7 @@ <h4 class="heading settled heading" data-level=6.3.4 id=interface-csskeyframesru
 		<dt><dfn class=idl-code data-dfn-for=CSSKeyFramesRule/deleteRule() data-dfn-type=argument data-export="" id=dom-csskeyframesruledeleterule-key>key<a class=self-link href=#dom-csskeyframesruledeleterule-key></a></dfn> of type <a class=idl-code data-link-type=interface title=domstring>DOMString</a>
 		<dd>
 			The key which describes the rule to be deleted. A percentage value between 
-            0% and 100%, or one of the keywords <span class=css data-link-type=maybe title=fro>fro</span> or <span class=css data-link-type=maybe title=to>to</span> which resolve to 0% and 
+            0% and 100%, or one of the keywords <span class=css data-link-type=maybe title=from>from</span> or <span class=css data-link-type=maybe title=to>to</span> which resolve to 0% and 
             100%, respectively.
 	</dl>