Method rfind_if

lib/swoc/include/swoc/TextView.h:1516–1522

template <typename F>
inline size_t
TextView::rfind_if(F const &pred) const {
  for (const char *spot = this->data_end(), *limit = this->data(); spot > limit;)
    if (pred(*--spot))
      return spot - this->data();
  return npos;
}

inline TextView &
TextView::ltrim(char c) {