Built-in filter that matches Telegram command updates.
Usage
# Match any command
filter ExGram.Router.Filters.Command
# Match a specific command
filter ExGram.Router.Filters.Command, :start
# Or using the built-in alias
filter :command, :start
filter :command # matches any commandOptions
nil— matches any command updateatom— matches a specific declared command (e.g.,:start)string— matches an undeclared command string (e.g.,"unknown_cmd")