Don't call AdjustPagebreak() in a loop, this seems useless

There doesn't seem to be any reason to call this function more than once
on the same cell as the existing implementations are idempotent and it's
difficult to see why this should ever not be the case.

include/wx/html/htmlcell.h

@@ -286,7 +286,6 @@ public:
     // few pixels up.
     //
     // Returned value : true if pagebreak was modified, false otherwise
-    // Usage : while (container->AdjustPagebreak(&p)) {}
     virtual bool AdjustPagebreak(int *pagebreak,
                                  const wxArrayInt& known_pagebreaks,
                                  int pageHeight) const;