Glossary: add TR.

wiki/src/contribute/glossary.mdwn

@@ -53,6 +53,9 @@ The words
 * **RM**: see Release Manager
 * **t-p-s**: `tails-persistence-setup`, AKA the [[Persistent Volume
   Assistant|doc/first_steps/persistence/configure]].
+* **Trusted reproducer**: the person verifying reproducibility of released
+  images
+* **TR**: see Trusted reproducer
 * **WB**: see WhisperBack.
 * **WhisperBack**: see *3.5 Feedback* in the [[contribute/design]]
   document.