Add a cabal target command

- Avoid list in the help
- Use establishProjectBaseContext
- Remove withContextAndSelectors
- Use rebuildInstallPlan and resolveTargets
- Extract targetForms
- Satisfy hlint
- Remove unnecessary do
- Use safeHead
- Call printPlanTargetForms for everything
- Remove planTargetForms
- Rework command description
- Remove script as a possible TARGET form
- Section help into; intro, targetFroms and ctypes
- Use pretty printing for examples
- Short form and long form
- Add a changelog entry
- Need nixStyleOptions for cabal-testsuite
  - unrecognized 'v2-target' option `-vverbose +markoutput +nowrap'
  - unrecognized 'v2-target' option `--builddir'
  - unrecognized 'v2-target' option `-j1'
- Use notice so target forms are marked output
- Add tests of target all, implicit and explicit
- Add tests of all:exes and all:tests
- Add test of all:benches
- Add tests with --enable-tests and --enable-benchmarks
- Warn that package targets display libs and exes
- Add package target tests
- Add path target tests
- Add component target tests
- Add c package with only a library
- Add tests for missing ctypes
- Exclude new-target from other commands
- Move target command to configuration group
- Add target command docs
- Add cabal target docs
- A significant change
- Drop cleans from tests
- Use noticeDoc to preserve indent
- Satisfy fourmolu
- Show the number of matches found matching query
- Change synopsis of command, target verb
- Remove disclosed, use show, WARN and NOTE
- Typo command singular
- Bring the command docs inline with --help docs
- Remove disclosing from changelog
- Only by default, not *only*.

Co-Authored-By: brandon s allbery kf8nh <allbery.b@gmail.com>