[css-font-loading] Slight rephrase.

Author: tabatkins

css-font-loading/Overview.bs

@@ -826,8 +826,7 @@ The <code>check()</code> method</h3>
 	The {{FontFaceSet/check()}} method of {{FontFaceSet}} will determine you can "safely"
 	render some provided text with a particular font list,
 	such that it won't cause a "font swap" later.
-	If the given text/font combo will not cause any font loads,
-	and does not rely on currently-loading fonts,
+	If the given text/font combo will render without attempting to use any unloaded or currently-loading fonts,
 	this method will return true;
 	otherwise, it returns false.
 
@@ -841,7 +840,7 @@ The <code>check()</code> method</h3>
 			as the text will be rendered in the UA's fallback font instead,
 			and won't trigger any font loads.
 		* If none of the specified fonts exist,
-			even tho this is technically similar to the previous case,
+			even though this is technically similar to the previous case,
 			in that text rendered with that font list would just use the UA fallback font.
 			This is because such a situation is almost certainly either a typo,
 			or the result of changing the name of a downloadable font