add stub for codeblock issue on macOS 10.14.x, or to revert to previous behavior

Author: tessus

Dark/userchrome.css

@@ -34,6 +34,14 @@ pre.CodeMirror-line span[role="presentation"] span.cm-comment {
 }
 /*---------------------------------------------------------------------------*/
 
+/*------ Editor: codeblock issue macOS 10.14.x (https://g0to.ca/0k7vF) ------*/
+/*
+div.CodeMirror div.cm-jn-code-block {
+	background-color: unset !important;
+}
+*/
+/*---------------------------------------------------------------------------*/
+
 /*------ Editor: text in brackets [ ] ---------------------------------------*/
 .cm-link-text {
 	color: var(--editor-text-in-brackets-color) !important;