Enhance stylelint rule config, remove dead CSS (#24472)

Make this stylelint rule match on more properties.

The dead CSS relates to the navbar, which currently has classes:

```
ui top secondary stackable main menu following bar light
```

Which means `.following.bar .top.menu` can never match, so remove this
dead CSS as well as inactive `z-index` and `left` on it.

Commits table striping becomes more visible on dark theme, but I don't
think it's worth introducing a new color until
https://github.com/go-gitea/gitea/pull/24423 is ready, which would have
to remove it again:

<img width="668" alt="Screenshot 2023-05-01 at 18 41 49"
src="https://user-images.githubusercontent.com/115237/235489873-6b272899-1d78-443a-872c-ee7731c269f9.png">
<img width="680" alt="Screenshot 2023-05-01 at 18 41 41"
src="https://user-images.githubusercontent.com/115237/235489878-1b9468af-c74f-48a6-a469-9eba57cfcb4d.png">

web_src/css/base.css

@@ -1228,8 +1228,6 @@ img.ui.avatar,
 }
 
 .following.bar {
-  z-index: 900;
-  left: 0;
   margin: 0 !important;
 }
 
@@ -1242,24 +1240,6 @@ img.ui.avatar,
   margin-top: 0;
 }
 
-.following.bar .top.menu a.item.brand {
-  padding-left: 0;
-}
-
-.following.bar .top.menu a.item:hover,
-.following.bar .top.menu .dropdown.item:hover,
-.following.bar .top.menu .dropdown.item.active {
-  background-color: transparent;
-}
-
-.following.bar .top.menu a.item:hover {
-  color: rgba(0, 0, 0, 0.45);
-}
-
-.following.bar .top.menu .menu {
-  z-index: 900;
-}
-
 .following.bar .fitted .svg {
   margin-right: 0;
   vertical-align: middle;

web_src/css/repository.css

@@ -1359,7 +1359,7 @@
 }
 
 .repository #commits-table.ui.basic.striped.table tbody tr:nth-child(2n) {
-  background-color: rgba(0, 0, 0, 0.02) !important;
+  background-color: var(--color-light) !important;
 }
 
 .repository #commits-table td.sha .sha.label,