TemplateReplaceArg takes an index i and returns a hook template string that the CLI will replace the template with the ith argument, after processing the passed flags.

TemplateReplaceFlagValue returns a hook template string that will be replaced by the flags value.

TemplateReplaceSubcommandName returns a hook template string that will be replaced by the CLI subcommand being executed Example: "you ran the subcommand: " + TemplateReplaceSubcommandName() when being executed after the command: `docker run --name "my-container" alpine` will result in the message: `you ran the subcommand: run`.

HookMessage represents a plugin hook response.