code: function preprocessMatchPath(segments) {
      const merged = mergeConsecutive(segments, '**');
      if (merged.length !== segments.length) {
          warn(`Consecutive '**' globs found
                (${segments.length - merged.length} excess).`);
      }
      segments = isolateGlobstarPattern(segments);
      segments = appendGlobstarIfTrailingSlash(segments);
      return mergeConsecutive([ ...segments,
                                ...(last(segments) === '**' ? ['*'] : []) ],
                              '**');
  }
docs: Normalize match path: Merge consecutive '**' segments and append a '*' to
  trailing '**' segment to match any file in folder)