Adds highlight to rebase edit/reword

Author: eamodio

src/webviews/apps/scss/rebase.scss

@@ -133,6 +133,18 @@ h4 {
 			border: 2px solid rgba(0, 153, 0, 1);
 			z-index: 3;
 		}
+
+		&::before {
+			display: inline-block;
+			content: ' ';
+			background-color: var(--color-background);
+			border-left: 2px solid rgba(0, 153, 0, 1);
+			height: 48px;
+			width: 2px;
+			margin-left: -18px;
+			position: absolute;
+			z-index: 1;
+		}
 	}
 
 	&.entry--squash,