chore(cmd): print shortHelp if longHelp is empty

[tbruyelle]

Currenlty, shortHelp is used when the command is listed from its parent command, and longHelp is used when the command is executed with its help flag.

What I found a little annoying is if longHelp is not provided, which is the case for the majority of commands, there's no text at all when the command is invoked with the help flag.

This change ensures the shortHelp is printed if longHelp is empty.

Example with `gno test` :

Before the change:

$ gno test -h
USAGE
  test [flags] <package> [<package>...]

FLAGS
  -precompile=false             precompile gno to go before testing
  -print-runtime-metrics=false  print runtime metrics (gas, memory, cpu cycles)
  -root-dir ...                 clone location of github.com/gnolang/gno (gnodev tries to guess it)
  -run ...                      test name filtering pattern
  -timeout 0s                   max execution time
  -update-golden-tests=false    writes actual as wanted in test comments
  -verbose=false                verbose output when running
  -with-native-fallback=false   use stdlibs/* if present, otherwise use supported native Go packages

error parsing commandline arguments: flag: help requested

After the change:

$ gno test -h
USAGE
  test [flags] <package> [<package>...]

Runs the tests for the specified packages.

FLAGS
  -precompile=false             precompile gno to go before testing
  -print-runtime-metrics=false  print runtime metrics (gas, memory, cpu cycles)
  -root-dir ...                 clone location of github.com/gnolang/gno (gnodev tries to guess it)
  -run ...                      test name filtering pattern
  -timeout 0s                   max execution time
  -update-golden-tests=false    writes actual as wanted in test comments
  -verbose=false                verbose output when running
  -with-native-fallback=false   use stdlibs/* if present, otherwise use supported native Go packages

error parsing commandline arguments: flag: help requested

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests
• Added new benchmarks to generated graphs, if any. More info here.

[tbruyelle]

ShortHelp shouldn't end with a dot. Eventually, a dot is added if ShortHelp is used when the command is executed with its help flag.

[moul]

I think it's better to let the point in the definition and have a more basic fprintf in command.go.

[tbruyelle]

Well, this ShortHelp is the only one that had a final dot, all others haven't.

In addition, if we add dots at the end of ShortHelp, this will result in this when listing sub-commands :

$ gno
USAGE
  <subcommand> [flags] [<arg>...]

Runs the gno development toolkit

SUBCOMMANDS
  mod         Manage gno.mod.
  test        Runs the tests for the specified packages.
  lint        Runs the linter for the specified packages.
  run         Runs the specified gno files.
  build       Builds the specified gno package.
  precompile  Precompiles .gno files to .go.
  clean       Removes generated files and cached data.
  repl        Starts a GnoVM REPL.
  doc         get documentation for the specified package or symbol (type, function, method, or variable/constant).

IMO I prefer without the final dot.

[moul]

Yep, agree 👍

[moul]

Suggested change

	fmt.Fprintf(&b, "%s.\n\n", c.shortHelp)
	fmt.Fprintf(&b, "%s\n\n", c.shortHelp)