super minor type in the quick tips. "it's" to "its"

astrid/res/values/strings.xml

@@ -364,7 +364,7 @@ Some things you may not know about Astrid:\n
 \n
 - To create a task, just start typing!\n
 - While editing a task, hit \'back\' to save it\n
-- Select a task & press 1-4 to quickly change it\'s priority\n
+- Select a task & press 1-4 to quickly change its priority\n
 - If a task has a deadline, long-press to postpone it\n
 \n
 Thanks for using Astrid!\n