provide option to disable fuzzy search on request basis

[bsushmith]

Is your feature request related to a problem? Please describe.
We have a field usage count based on which we prioritize our search results. This was enabled through the rankby parameter introduced in PR for this exact purpose.

Compass also has fuzziness enabled by default on the search queries - Link. This Fuzziness combined with the usage count based ranking gives weird results many times as the fuzziness results get prioritized due to high usage count, where as the exact match term might have slightly less usage count but get de-prioritized in the search ranking - which is not a good experience.

In our case, expectation would be to show results somewhat similar to like below, as we would prefer to show exact match term with higher usage count compared to a fuzzy search related result(which might not be relevant at all)

-- desired output
{
  exact match results ranked on usage count
  ...
  fuzzy results ranked on usage count
}

It is kind of not possible to do both sorts of ranking at the same time. and one of the solutions would be to let user define if they need fuzziness in their search results or not. This would enable one to switch off fuzzy if needed on case by case basis.

Describe the solution you'd like
A new param in the search API to disable fuzzyness keeping the API backward compatible.
param - disable_fuzzy