pr_dash: fix broken Slack links in --slack output

The <url|text> mrkdwn link syntax gets mangled by Slack's rich text
editor, encoding the pipe as %7C and breaking the URL. Use bare URLs
instead, which Slack auto-links reliably.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: thiagowfx

pr_dash/pr_dash.sh

@@ -601,7 +601,7 @@ render_slack() {
             (if $rv_e != "" then " " + $rv_e else "" end) +
             " " +
             (if .isDraft then "[draft] " else "" end) +
-            "<\(.url)|#\(.number) \(.title)>" +
+            "\(.url) \(.title)" +
             " \u00b7 " + (.createdAt | age) +
             (if .reviewers and (.reviewers | length) > 0 then " \u00b7 " + (.reviewers | join(", ")) else "" end)
         ),