Forbid setting hints for multi-line text controls.

This doesn't work anyhow, so make it explicit by asserting if an attempt to do
it is made. And document this.

Also add a test of SetHint() to the text sample to verify it still works.

Closes #14456.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72010 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/textcmn.cpp

@@ -1139,6 +1139,18 @@ bool wxTextCtrlBase::EmulateKeyPress(const wxKeyEvent& event)
     return handled;
 }
 
+// ----------------------------------------------------------------------------
+// Other miscellaneous stuff
+// ----------------------------------------------------------------------------
+
+bool wxTextCtrlBase::SetHint(const wxString& hint)
+{
+    wxCHECK_MSG( IsSingleLine(), false,
+                 wxS("Hints can only be set for single line text controls") );
+
+    return wxTextEntry::SetHint(hint);
+}
+
 // do the window-specific processing after processing the update event
 void wxTextCtrlBase::DoUpdateWindowUI(wxUpdateUIEvent& event)
 {