Update 7-animation/2-css-animations/article.md

Co-authored-by: Muhammed Zakir <8190126+MuhammedZakir@users.noreply.github.com>

Author: peachesontour

7-animation/2-css-animations/article.md

@@ -129,7 +129,7 @@ stripe.onclick = function() {
 
 ## transition-timing-function
 
-The timing function describes how the animation process is distributed along its timeline. Will it start slowly and then go fast or vice versa.
+The timing function describes how the animation process is distributed along its timeline. Will it start slowly and then go fast, or vice versa.
 
 It appears to be the most complicated property at first. But it becomes very simple if we devote a bit time to it.