lncli: show subcommands in lncli help <command>

[manantlerio]

Change Description

Fixes #7975.

lncli help wallet printed only the name, usage and category of the wallet
command, while lncli wallet --help also listed everything below it:

NAME:
   lncli wallet - Interact with the wallet.

USAGE:
   lncli wallet [arguments...]

CATEGORY:
   Wallet

The cli library's help command always renders through cli.ShowCommandHelp,
which uses the flat CommandHelpTemplate. That template has no section for
subcommands. The --help flag takes a different path: a command that has
subcommands is turned into its own sub-application, which is rendered with
SubcommandHelpTemplate and does list them.

This replaces the library's help command with one that hands a command that
has subcommands to that same sub-application path, so both ways of asking print
the same thing. Commands without subcommands, and names that don't resolve to a
command at all, keep going through cli.ShowCommandHelp unchanged.

The library only registers the global help flag if the application doesn't
declare a command called help itself, so cli.HelpFlag is now added to
app.Flags by hand. lncli --help and lncli -h are unaffected.

After:

NAME:
   lncli wallet - Interact with the wallet.

USAGE:
   lncli wallet command [command options] [arguments...]

COMMANDS:
   estimatefeerate    Estimates the on-chain fee rate to achieve a confirmation target.
   pendingsweeps      List all outputs that are pending to be swept within lnd.
   bumpfee            Bumps the fee of an arbitrary input/transaction.
   ...
   addresses          Interact with wallet addresses.

OPTIONS:
   --help, -h  show help

Steps to Test

Build lncli and compare the two ways of asking for help:

lncli help wallet
lncli wallet --help

The output is now identical. The same holds for the other commands that have
subcommands (profile, wtclient, peers, chain). lncli help sendcoins,
lncli help, lncli --help and lncli help <unknown> (still exit code 3) are
unchanged.

Unit tests:

go test ./cmd/commands/ -run TestHelp -v

Pull Request Checklist

Testing

• Your PR passes all CI checks.
• Tests covering the positive and negative (error paths) are included.
• Bug fixes contain tests triggering the bug to prevent regressions.

Code Style and Documentation

• The change is not insubstantial. Typo fixes are not accepted to fight bot spam.
• The change obeys the Code Documentation and Commenting guidelines, and lines wrap at 80.
• Commits follow the Ideal Git Commit Structure.
• Any new logging statements use an appropriate subsystem and logging level.
• Any new lncli commands have appropriate tags in the comments for the rpc in the proto file.
• There is a change description in the release notes, or [skip ci] in the commit message for small changes.

[github-actions]

🟡 PR Severity: MEDIUM

file classification | 4 files | 180 lines changed

🟡 Medium (2 files)

• cmd/commands/cmd_help.go - new file under cmd/commands/*, CLI client help-rendering logic
• cmd/commands/main.go - CLI app wiring (registers help flag/command)

🟢 Low (2 files)

• cmd/commands/cmd_help_test.go - test-only file
• docs/release-notes/release-notes-0.22.0.md - release notes

Analysis

All substantive changes are confined to cmd/commands/*, which is CLI (lncli) client code and is classified MEDIUM regardless of the fact that the affected commands (e.g. wallet, peers, chain) share names with server-side critical packages — per the classification rules, cmd/* does not inherit severity from similarly-named server packages. The change only alters how lncli help <command> renders output (delegating to the library's existing subcommand help path) and does not touch any RPC, wallet, or wire-protocol logic. File count (2 non-test/non-doc files) and line count (180 total, well under the 500-line/20-file bump thresholds) do not warrant a severity bump.

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