Expand 'cabal init' docs to explain what -w means in that context

[Mikolaj]

Probably -w just uses a different GHC to run. But it could potentially set base bounds based on the GHC (please confirm it does not) or write the GHC to cabal.project (it does not), so a more verbose commandline help text would prevent confusion by clearly stating this is not the case.

[andreabedini]

@Mikolaj I can confirm cabal init uses -w to set base lower bounds (at least version 3.6.2.0)

$ mkdir my-project 
$ cd my-project/
~/my-project $ cabal init -w ghc-8.0
Guessing dependencies...

Generating LICENSE...
Warning: unknown license type, you must put a copy in LICENSE yourself.
Generating CHANGELOG.md...
Generating app/Main.hs...
Generating my-project.cabal...

Warning: no synopsis given. You should edit the .cabal file and add one.
You may want to edit the .cabal file and add a Description field.

$ grep base my-project.cabal 
    build-depends:    base ^>=4.9.1.0

~/my-project $ rm -rf *
~/my-project $ cabal init -w ghc-8.10

Guessing dependencies...

Generating LICENSE...
Warning: unknown license type, you must put a copy in LICENSE yourself.
Generating CHANGELOG.md...
Generating app/Main.hs...
Generating my-project.cabal...

Warning: no synopsis given. You should edit the .cabal file and add one.
You may want to edit the .cabal file and add a Description field.

$ grep base my-project.cabal 
    build-depends:    base ^>=4.14.3.0

[Mikolaj]

Whoa, I had no idea. Then the docs are even more important, given that the semantics of -w differs so much between commands.