[minor] used @text-color for color attribute instead of black

frappe/public/css/form.css

@@ -601,10 +601,9 @@ select.form-control {
 .control-code.bold {
   height: 400px;
   font-family: Monaco, "Courier New", monospace;
-  color: black;
+  color: #36414C;
   font-size: 12px;
   line-height: 1.7em;
-  border: none;
 }
 .delivery-status-indicator {
   display: inline-block;

frappe/public/less/form.less

@@ -749,10 +749,9 @@ select.form-control {
 .control-code, .control-code.bold {
 	height: 400px;
 	font-family: Monaco, "Courier New", monospace;
-	color: black;
+	color: @text-color;
 	font-size: 12px;
 	line-height: 1.7em;
-	border: none;
 }
 
 .delivery-status-indicator {