fix go to file link for mirror repository (#19983)

the `BaseRepo` not always exit, should
use `Repository`.

Signed-off-by: a1012112796 <[email protected]>

Author: a1012112796

templates/repo/home.tmpl

@@ -74,7 +74,7 @@
 					</div>
 				{{end}}
 				<div class="fitted item mx-0">
-					<a href="{{.BaseRepo.Link}}/find/{{.BranchNameSubURL}}" class="ui compact basic button">
+					<a href="{{.Repository.Link}}/find/{{.BranchNameSubURL}}" class="ui compact basic button">
 						{{.i18n.Tr "repo.find_file.go_to_file"}}
 					</a>
 				</div>