Fixes in grammar and punctuation in English translatable messages

Author: amire80

app/src/main/res/values/strings.xml

@@ -314,11 +314,11 @@
   <string name="quiz_back_button">If you carry on uploading images that require deletion, your account will likely be banned. Are you sure you want to end the quiz?</string>
   <string name="quiz_alert_message">More than %1$s of the images you uploaded have been deleted. If you carry on uploading images that require deletion, your account will likely be banned.\n\nWould you like to view the tutorial again and then take a quiz to help you learn what type of images you should or shouldn\'t upload?</string>
   <string name="selfie_answer">Selfies do not have much encyclopedic value. Please do not upload a picture of yourself unless you already have a Wikipedia article about you.</string>
-  <string name="taj_mahal_answer">Pictures of monuments and outside scenery is OK to upload in most countries. Please note that temporary art installations outside are often copyrighted and not OK to upload.</string>
+  <string name="taj_mahal_answer">Pictures of monuments and outside scenery are OK to upload in most countries. Please note that temporary art installations outside are often copyrighted and not OK to upload.</string>
   <string name="screenshot_answer">Screenshots of websites are considered derivatives works and subject to any copyright on the website itself. These can be used after permission from the author. Without such permission, any art you create based on their work is legally considered an unlicensed copy owned by the original author.</string>
   <string name="blurry_image_answer">One of the goals of Commons is to gather quality images. Therefore, blurry images shouldn\'t be uploaded. Always try to take nice pictures with good lighting.</string>
   <string name="construction_event_answer">Pictures showing technology or culture are very welcome on Commons.</string>
-  <string name="warning_for_image_reverts">WARNING : More than %1$s of the images you uploaded have been deleted. If you carry on uploading images that require deletion, your account will likely be banned.</string>
+  <string name="warning_for_image_reverts">WARNING: More than %1$s of the images you uploaded have been deleted. If you carry on uploading images that require deletion, your account will likely be banned.</string>
   <string name="congratulatory_message_quiz">You got %1$s of the answers correct. Congratulations!</string>
   <string name="warning_for_no_answer">Select one of the two options to answer the question</string>
   <string name="user_not_logged_in">Login session expired, please log in again.</string>