Move link styling to nimitta.scss for global coverage

The previous fix in content-perma.scss only applied to content pages,
not tag pages. Move the .copyright div a override into nimitta.scss
(inside .content_links) so it applies everywhere. Revert
content-perma.scss to its original state.

Signed-off-by: Tim Ren <137012659+xr843@users.noreply.github.com>

Author: xr843

_sass/nimitta.scss

@@ -540,6 +540,11 @@ h1.overlay-into-banner {
     a {
         font-family: $ui-font-family;
     }
+    .copyright div a {
+        font-family: inherit;
+        text-decoration: underline;
+        color: inherit;
+    }
 }
 
 main header.post-header {
@@ -636,4 +641,4 @@ ol {
             font-size: 14px;
         }
     }
-}
+}

assets/css/content-perma.scss

@@ -147,11 +147,6 @@ div.content_links {
         padding: 5px;
         border-radius: 3px;
         font-size: 96%;
-        a {
-            text-decoration: underline;
-            color: inherit;
-            font-family: inherit;
-        }
     }
 }