Added match regex & styling for null

Author: kinnell

grammars/transact-sql.cson

@@ -21,4 +21,8 @@ patterns: [
     match: '\\b[0-9]+(\\.[0-9]+)?\\b'
     name: 'numeric'
   }
+  {
+    match: '\\b(null|not null)\\b'
+    name: 'null'
+  }
 ]

styles/language-transact-sql.less

@@ -1,6 +1,7 @@
 @color-gray:   #5C6370;
 @color-green:  #98C379;
 @color-orange: #D19A66;
+@color-pink:   #DD78AE;
 @color-red:    #E06C75;
 
 atom-text-editor {
@@ -17,4 +18,7 @@ atom-text-editor {
   .syntax--numeric {
     color: @color-orange;
   }
+  .syntax--null {
+    color: @color-pink;
+  }
 }