Add missing git-link-commit-sourcehut function and fix alist reference

Co-authored-by: sshaw <17570+sshaw@users.noreply.github.com>

Author: Copilot

git-link-test.el

@@ -334,6 +334,11 @@
   (should (equal "https://sourcegraph.com/user/repo/-/commit/abc123"
                  (git-link-commit-sourcegraph "https://sourcegraph.com" "user/repo" "abc123"))))
 
+(ert-deftest git-link-commit-sourcehut ()
+  "Test git-link-commit-sourcehut function."
+  (should (equal "https://git.sr.ht/~user/repo/commit/abc123"
+                 (git-link-commit-sourcehut "https://git.sr.ht" "~user/repo" "abc123"))))
+
 (ert-deftest git-link-commit-codecommit ()
   "Test git-link-commit-codecommit function."
   (should (equal "https://us-west-2.console.aws.amazon.com/codesuite/codecommit/repositories/repo/commit/abc123"

git-link.el

@@ -255,7 +255,7 @@ As an example, \"gitlab\" will match with both \"gitlab.com\" and
   :group 'git-link)
 
 (defcustom git-link-commit-remote-alist
-  '(("git.sr.ht" git-link-commit-github)
+  '(("git.sr.ht" git-link-commit-sourcehut)
     ("codeberg.org" git-link-commit-codeberg)
     ("github" git-link-commit-github)
     ("bitbucket" git-link-commit-bitbucket)
@@ -672,6 +672,12 @@ is prepended to it."
                                 (format "L%s-%s" start end)
                               (format "L%s" start)))))))
 
+(defun git-link-commit-sourcehut (hostname dirname commit)
+  (format "%s/%s/commit/%s"
+	  hostname
+	  dirname
+	  commit))
+
 (defun git-link-commit-gitlab (hostname dirname commit)
   (format "%s/%s/-/commit/%s"
 	  hostname