Sorry I can’t offer up, for now, more than this as an update to forum.c.

$ fossil diff
Index: src/forum.c
==================================================================
--- src/forum.c
+++ src/forum.c
@@ -1520,11 +1520,11 @@
     @ <br><label><input type="checkbox" name="domod" %s(PCK("domod"))> \
     @ Require moderator approval</label>
     @ <br><label><input type="checkbox" name="showqp" %s(PCK("showqp"))> \
     @ Show query parameters</label>
     @ <br><label><input type="checkbox" name="fpsilent" %s(PCK("fpsilent"))> \
-    @ Do not sent notification emails</label>
+    @ Do not send notification emails</label>
     @ </div>
   }
 }
 
 /*