Typo suggestions in more places in stack

[mgsloan]

See #158 , where it will suggest near matches of the user's input. This only works for things like stack build pkg-0.0.... It'd be great to have fuzzy suggestions for all of the following:

• Targets. Ideally this would handle fuzzy suggestions of package names and component names. Bonus would also be supporting fuzzy suggestions of dirs, but that's not a big deal.
• extra-deps. See also Typos in extra-deps aren't detected #1521
• filepaths? For example --stack-yaml
• more?

Ideally, these suggestions would share the same system as shell completion (see #1343 and #832 . This way we can get checking and suggestions from the same mechanism!

(but of course, PRs adding any of these will be accepted, no need to do it all)

[mgsloan]

• Fields in .cabal files.
  • Most important is build-depends (see Mention that package names are case-sensitive #2111 (comment))
  • It would also be good to support other various strings like paths and modules.

[mgsloan]

• Unknown packages in dependencies - use fuzzy matching with all known hackage packages. See "Stack configuration has no specified verson" - could this error be improved? #2713