Botan3 no longer adds the prefixes that Monotone tries to clear

--- mtn-src/src/transforms.cc	2026-08-05 21:59:22.344598683 +0200
+++ mtn-src/src/transforms.cc	2026-08-05 21:59:52.318528753 +0200
@@ -67,12 +67,7 @@
       || typeid(e) == typeid(Botan::Invalid_Argument)
       || typeid(e) == typeid(Botan::Integrity_Failure))
     {
-      // clean up the what() string a little: throw away the
-      // "botan: TYPE: " part...
       string w(e.what());
-      string::size_type pos = w.find(':');
-      pos = w.find(':', pos+1);
-      w = string(w.begin() + pos + 2, w.end());
 
       // ... downcase the rest of it and replace underscores with spaces.
       for (string::iterator p = w.begin(); p != w.end(); p++)