MDL-36954 question bank: stop centring question name.

This was a regression caused by MDL-21625. These CSS changes
put the display back to how it was, while leaving the table
cell as a TD  for accessibility.

theme/base/style/question.css

@@ -33,6 +33,8 @@ body.jsenabled #qtypechoicecontainer {display: block;}
 #categoryquestions { margin: 0; }
 #categoryquestions td,
 #categoryquestions th { padding: 0 0.2em; }
+#categoryquestions th { text-align: left; font-weight: normal; }
+.dir-rtl #categoryquestions th { text-align: right; }
 .questionbank .singleselect { margin: 0; }
 
 /* Question editing form */