[css-transitions] Typo fix.

Author: dbaron

css-transitions/Overview.bs

@@ -1763,7 +1763,7 @@ that allows user needs to interact with author styles.
 This specification interacts with the cascade,
 but since it only allows animation between values
 that result from the existing cascade rules,
-it does not interfere with user's ability to force
+it does not interfere with the user's ability to force
 CSS properties to have particular values.
 
 The cascade also allows users to disable transitions entirely

css-transitions/Overview.html

@@ -1337,7 +1337,7 @@ <h3 class="heading settled" data-level="11.2" id="accessibility-cascade"><span c
 This specification interacts with the cascade,
 but since it only allows animation between values
 that result from the existing cascade rules,
-it does not interfere with user’s ability to force
+it does not interfere with the user’s ability to force
 CSS properties to have particular values.</p>
    <p>The cascade also allows users to disable transitions entirely
 by overriding the transition properties.</p>