remove white space between ln nos and code

src/sass/_chroma_github.scss

@@ -57,6 +57,7 @@
 }
 .chroma .lntable td:first-child {
   padding-right: 0.5em;
+  background-color: $color-code;
 }
 .chroma .lntable td:first-child code {
   border-right: 1px solid #dcdfe3;