Edit one link destination inside an internationalized string...

... Apply substituion to the result of translation lookup, assuming the
translator preserved the url verbatim.  (But in future, we should not have
urls inside translated strings.)

Problem is that the page faq_opening_and_saving_files.html will exist in the
2.2.0 manual online, but the anchor #midi will no longer exist on it.

This help link comes up only when import fails (perhaps the file is corrupt)
and the user presses the help button.

This help goes through an unusual code path that never uses local help.  That
could stand fixing in future.

src/HelpText.cpp

@@ -199,6 +199,23 @@ wxString TitleText( const wxString & Key )
    return Key;
 }
 
+namespace {
+   // This is ugly transitional stuff for 2.2.0 only
+   // The target string may have been localized but contains a link that we
+   // need to change to fix remote help, while preserving the translated
+   // material.
+   // In future we should not put Wiki and HTML markup inside
+   // internationalized strings!  Descriptive text for the link should be
+   // localized separately, then replaced using string formatting.
+   wxString Substitute(wxString target,
+                   const wxString &given,
+                       const wxString &replacement) {
+      target.Replace(given, replacement);
+      return target;
+
+   }
+}
+
 static wxString HelpTextBuiltIn( const wxString & Key )
 {
    // PRL:  Is it necessary to define these outside of conditional compilation so that both get into the .pot file?
@@ -261,10 +278,14 @@ static wxString HelpTextBuiltIn( const wxString & Key )
 compressed WAV files from portable recorders and audio from video files) if you download and install \
 the optional [[http://manual.audacityteam.org/man/faq_opening_and_saving_files.html#foreign| \
 FFmpeg library]] to your computer.") + wxT("</p><p>") +
+Substitute(
          _("You can also read our help on importing \
 [[http://manual.audacityteam.org/man/faq_opening_and_saving_files.html#midi|MIDI files]] \
 and tracks from [[http://manual.audacityteam.org/man/faq_opening_and_saving_files.html#fromcd| \
-audio CDs]].") + wxT("</p>")
+audio CDs]]."),
+                       wxT("faq_opening_and_saving_files.html#midi"),
+                       wxT("playing_and_recording.html#midi")
+) + wxT("</p>")
       );
    }