Fix infinite loop in wxDateTime::Format() when fields width was used.

Just add a missing increment of the loop variable.

See #12451.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65496 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/datetimefmt.cpp

@@ -648,9 +648,10 @@ wxString wxDateTime::Format(const wxString& formatp, const TimeZone& tz) const
 
                 default:
                     // is it the format width?
-                    fmt.Empty();
-                    while ( *p == wxT('-') || *p == wxT('+') ||
-                            *p == wxT(' ') || wxIsdigit(*p) )
+                    for ( fmt.clear();
+                          *p == wxT('-') || *p == wxT('+') ||
+                            *p == wxT(' ') || wxIsdigit(*p);
+                          ++p )
                     {
                         fmt += *p;
                     }