Nested code lines now no longer display the hover border left. (#24686)

* Nested code lines now no longer display the hover border left.

* Added fix for both light and hc themes.

extensions/markdown/media/markdown.css

@@ -64,6 +64,10 @@ body.showEditorSelection li.code-line:hover:before {
 	border-left: 3px solid rgba(0, 0, 0, 0.40);
 }
 
+.vscode-light.showEditorSelection .code-line .code-line:hover:before {
+	border-left: none;
+}
+
 .vscode-dark.showEditorSelection .code-active-line:before {
 	border-left: 3px solid rgba(255, 255, 255, 0.4);
 }
@@ -72,6 +76,10 @@ body.showEditorSelection li.code-line:hover:before {
 	border-left: 3px solid rgba(255, 255, 255, 0.60);
 }
 
+.vscode-dark.showEditorSelection .code-line .code-line:hover:before {
+	border-left: none;
+}
+
 .vscode-high-contrast.showEditorSelection .code-active-line:before {
 	border-left: 3px solid rgba(255, 160, 0, 0.7);
 }
@@ -80,6 +88,10 @@ body.showEditorSelection li.code-line:hover:before {
 	border-left: 3px solid rgba(255, 160, 0, 1);
 }
 
+.vscode-high-contrast.showEditorSelection .code-line .code-line:hover:before {
+	border-left: none;
+}
+
 img {
 	max-width: 100%;
 	max-height: 100%;