utils: fix .text-* classes not applying to <p>

scss/_utils.scss

@@ -14,17 +14,19 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-.text-center {
-    text-align: center;
-}
+@mixin text-align($align) {
+    .text-$align {
+        text-align: $align;
 
-.text-left {
-    text-align: left;
+        p {
+            text-align: $align;
+        }
+    }
 }
 
-.text-right {
-    text-align: right;
-}
+@include text-align(center);
+@include text-align(left);
+@include text-align(right);
 
 .text-green {
     color: $color_green;