Fix almost all warnings

[alicebob]

Most should be fine, but the last two commits might be too big a diff. Up to you what you do with this.

There are a few warnings left in a CLI module, but that one seems used only in tests (I'm not sure how to fix them).

[alicebob]

For #302

[avh4]

Did qualifying this help fix warnings, or was this just an additional cleanup?

[alicebob]

It's for these 4 warnings:

[53 of 61] Compiling Parse.Type       ( parser/src/Parse/Type.hs, .stack-work/dist/x86_64-linux-nopie/Cabal-1.24.2.0/build/Parse/Type.o )

.../elm-format/parser/src/Parse/Type.hs:41:13: warning: [-Wname-shadowing]
    This binding for ‘base’ shadows the existing binding
      imported from ‘AST.V0_16’ at parser/src/Parse/Type.hs:8:1-16

.../elm-format/parser/src/Parse/Type.hs:42:14: warning: [-Wname-shadowing]
    This binding for ‘fields’ shadows the existing binding
      imported from ‘AST.V0_16’ at parser/src/Parse/Type.hs:8:1-16

.../elm-format/parser/src/Parse/Type.hs:91:24: warning: [-Wname-shadowing]
    This binding for ‘first’ shadows the existing binding
      imported from ‘AST.V0_16’ at parser/src/Parse/Type.hs:8:1-16

.../elm-format/parser/src/Parse/Type.hs:91:31: warning: [-Wname-shadowing]
    This binding for ‘rest’ shadows the existing binding
      imported from ‘AST.V0_16’ at parser/src/Parse/Type.hs:8:1-16

Since thse names of the exported methods from AST.V0_16 are so generic I choose to solve it with qualifying the import. Same reasoning for the other file in this PR where AST.V0_16 is imported.

[avh4]

🤔 Why did this not lead to crashes before? Is NoInputs actually used anywhere?

[alicebob]

src/ElmFormat.hs:

                    case (elmVersionResult, determineWhatToDoFromConfig config resolvedInputFiles) of
                        (_, Left NoInputs) ->
                            (handleParseResult $ Flags.showHelpText defaultVersion elmFormatVersion experimental)
                                >> exitFailure

                        (_, Left message) ->
                            exitWithError message
...

exitWithError uses showErrorMessage (which is what the warning is about). So the NoInputs case is effectively impossible because it is handled in a special way.

[avh4]

Great, thanks! I added 45c8e6b...101460c