revert(docs): remove sponsor button changes

Author: kdroidFilter

docs/overrides/partials/header.html

@@ -53,17 +53,3 @@
 .md-social {
   display: none;
 }
-
-/* Sponsor heart button in header */
-.md-source__sponsor {
-  display: inline-flex;
-  align-items: center;
-  margin-right: 0.6rem;
-  vertical-align: middle;
-  opacity: 0.8;
-  transition: opacity 0.2s;
-}
-
-.md-source__sponsor:hover {
-  opacity: 1;
-}

docs/stylesheets/extra.css

@@ -7,7 +7,6 @@ edit_uri: edit/main/docs/
 
 theme:
   name: material
-  custom_dir: docs/overrides
   palette:
     - media: "(prefers-color-scheme: light)"
       scheme: default
@@ -97,5 +96,3 @@ extra:
   social:
     - icon: fontawesome/brands/github
       link: https://github.com/kdroidFilter/Nucleus
-    - icon: simple/kofi
-      link: https://ko-fi.com/lomityaesh