[Azure Search] Consider supporting misspelled terms

[loic-sharma]

Is your feature request related to a problem? Please describe.

Our data shows that ~7.4% of "legacy" and ~1.5% "preview" search queries have no results. Many of these queries are due to misspelled terms.

See https://github.com/NuGet/NuGetGallery/issues/7128#issuecomment-515607493 for data analysis.

Describe the solution you'd like

Consider adding fuzzy search to our queries: https://docs.microsoft.com/en-us/azure/search/search-get-started-portal#fuzzy-search

Additional context

• Do more data analysis:
  • What are the most common misspelled terms?
  • What edit distance should we support for fuzzy search?
• Should multi-term queries support misspellings?
• Should scoped terms support misspellings?
• Should we suggest another term instead? Similar to Google's "Did you mean XYZ?"

[joelverhagen]

Bounce should decrease and % of search queries that have no results must go down (as a ship gate, otherwise how do we measure success of this change).

[loic-sharma]

Verify that this doesn't make typosquatting worse. Find all package ids, determine how many are within 1/2/3 edit distances