Add DidYouMean suggestions for missing templates

[jhawthorn]

@seejohnrun and I wrote this together on his Twitch stream a few months ago, and it took me forever to actually submit. Oops! 😅

This PR adds DidYouMean spelling suggestions on MissingTemplate errors.

Missing partial test/_partail with {:locale=>[:en], :formats=>[:html, :text, :js, :css, :ics, :csv, :vcf, :vtt, :png, :jpeg, :gif, :bmp, :tiff, :svg, :mpeg, :mp3, :ogg, :m4a, :webm, :mp4, :otf, :ttf, :woff, :woff2, :xml, :rss, :atom, :yaml, :multipart_form, :url_encoded_form, :json, :pdf, :zip, :gzip], :variants=>[], :handlers=>[:raw, :erb, :html, :builder, :ruby]}.

Searched in:
  * "/Users/jhawthorn/src/rails/actionview/test/fixtures"

Did you mean?  test/_partial
               test/_partialhtml
               test/_partial_only
               test/_partial_iteration_1
               test/_partial_iteration_2
               test/_partial_with_layout

We tried to do this efficiently, knowing that many applications have thousands of templates. Our approach was to match prefixes separately from names (ie. with users/_form we'd score users and _form separately). Since we have multiple prefixes we're searching for (the inheritance chain of the controller) this reduces the amount of scoring we have to do. We also able to reuse scoring of the template names because action names are commonly reused (show, edit, etc.). To combine the two scores we add them together, which isn't necessarily "correct", but experimentally it provided the matches we hoped for.

In the case that there is a template which matches by virtual_path but we got a MissingTemplate for another reason (probably details not matching) we don't provide suggestions. In the future I'd like to add suggestions for mismatched details as well.