avfilter/buffersink: add color_spaces, color_ranges params

An oversight in my previous series. This omission slipped under the
radar because fftools/ffmpeg_filter.c did not use these options, instead
preferring to insert an explicit format filter.

libavfilter/buffersink.h

@@ -55,6 +55,8 @@
  * The format can be constrained by setting options, using av_opt_set() and
  * related functions with the AV_OPT_SEARCH_CHILDREN flag.
  *  - pix_fmts (int list),
+ *  - color_spaces (int list),
+ *  - color_ranges (int list),
  *  - sample_fmts (int list),
  *  - sample_rates (int list),
  *  - ch_layouts (string),