Sample text of toolbar button is ignored when title text exists.
Steps to reproduce:
1. Open an edit window.
2. Press a toolbar button for external link insertion.
3. Check the inserted text.
Expected:
[[http://example.com|External Link]]
Actual:
[[External Link]]
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Enbugged on:
https://github.com/splitbrain/dokuwiki/commit/5e7a292691951a0fa0a18f06c8b9bcfb509a032d#L12R75