feat(pulls): show PR URL in detail view (#1036)

Fixes #1035.

## Summary
- include the pull request URL in `tea pr <number>` detail output
- keep `tea pr create` output to one URL by relying on the shared detail renderer
- add a focused regression test

## Tests
- `go test ./modules/print`
- `go test ./...`

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Leon Müller <mueller4leon@gmail.com>
Reviewed-on: https://gitea.com/gitea/tea/pulls/1036
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: LeonM <206012+leonm@noreply.gitea.com>
Co-committed-by: LeonM <206012+leonm@noreply.gitea.com>

modules/print/pull_test.go

@@ -99,6 +99,17 @@ func TestFormatCIStatusAllStates(t *testing.T) {
 	}
 }
 
+func TestPullDetailsIncludesHTMLURL(t *testing.T) {
+	pr := newTestPR(8, "Crm wip")
+	pr.HTMLURL = "https://gitea.example.com/owner/repo/pulls/8"
+
+	out := captureStdout(t, func() {
+		PullDetails(pr, nil, nil)
+	})
+
+	assert.Contains(t, out, pr.HTMLURL)
+}
+
 func TestPullsListWithCIField(t *testing.T) {
 	prs := []*gitea.PullRequest{
 		newTestPR(1, "feat: add feature"),