fix(tabsbar): Fix close button overlay offset

Closes #897

Author: rafaelmardojai

theme/parts/tabsbar.css

@@ -277,11 +277,10 @@ tabs#tabbrowser-tabs {
 					background: linear-gradient(to left, var(--gnome-tabbar-tab-close-overlay-bg) 50%, transparent);
 					border-radius: 0 6px 6px 0;
 					content: "";
-					height: calc(100% - 4px);
+					height: 100%;
 					opacity: 0;
 					position: absolute;
-					right: 2px;
-					top: 2px;
+					right: 0px;
 					transition: opacity var(--gnome-tab-animation-time) linear;
 					width: 55px;
 					z-index: 99;