Fix FT.Search Limit argument and add CountOnly argument for limit 0 0

[ofekshenawa]

Adding a new boolean flag, CountOnly, to the FTSearchOptions struct to decouple count-only behavior from the default limit parameters.
Previously, it wasn't possible to input 0 0 for LimitOffset and Limit Now, with the CountOnly flag, users can explicitly signal a count-only query.
When CountOnly is set to true, the FT.SEARCH command builder appends LIMIT 0 0, ensuring that only the total count of matching documents is returned. When CountOnly is false, the provided LimitOffset and Limit values are used as usual.

[ndyakov]

Left comment regarding naming, I do think maybe CountsOnly will be the best we can do right now:

    CountOnly  bool // when true, sends LIMIT 0 0 to only get count

[elena-kolevska]

@ofekshenawa when this is merged please ping the docs team to create a new doctests example with a CountOnly example, or try updating it yourself and then ask their help with marking it up so it shows up properly in the docs.

[ndyakov]

LGTM, thank you!

[ndyakov]

@andy-stark-redis bringing this to your attention. Can we please add a doctest for this case?

[andy-stark-redis]

@andy-stark-redis bringing this to your attention. Can we please add a doctest for this case?

@ndyakov Sure, no problem :-)