fix border radius top left for descriptions

app/assets/stylesheets/generic/gfm.scss

@@ -4,6 +4,7 @@
 .issue-form, .merge-request-form, .wiki-form {
   .description {
     height: 20em;
+    border-top-left-radius: 0;
   }
 }
 
@@ -17,4 +18,4 @@
   .description {
     height: 14em;
   }
-}
\ No newline at end of file
+}