custom.css: make inline <code> look less alarming

Default is `#e74c3c` which reads like "error", changed to a dark orange which seems more neutral, but still "sticks out" enough for skimming purposes.

Author: mrienstra

src/_static/css/custom.css

@@ -15,6 +15,10 @@ code {
     color: rgb(51, 51, 51);
 }
 
+.rst-content code.literal, .rst-content tt.literal {
+    color: #a34400;
+}
+
 .rst-content .section ul p {
     margin-bottom: 0px !important;
 }