container: finance: lib_plugins: update usage help

- Clarify usage, add examples, note plugin support type
  * finance's `plugins` only supports shell-based plugins
    - To use `root` plugins, use `root` command (see `root help`)

container/src/finance/lib/internal/lib_plugins.bash

@@ -2,7 +2,7 @@
 
 # docker-finance | modern accounting for the power-user
 #
-# Copyright (C) 2024 Aaron Fiore (Founder, Evergreen Crypto LLC)
+# Copyright (C) 2024-2025 Aaron Fiore (Founder, Evergreen Crypto LLC)
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -65,18 +65,39 @@ function lib_plugins::__parse_args()
   local -r _usage="
 \e[32mDescription:\e[0m
 
-  Execute a categorical plugin
+  Execute a categorical shell plugin (non-\`root\`)
+
+  NOTE: for \`root\` plugins, see \`root help\`
 
 \e[32mUsage:\e[0m
 
-  $ $global_usage <repo${global_arg_delim_1}plugin | custom${global_arg_delim_1}plugin> [args]
+  $ $global_usage [help | [TAB COMPLETION]] [args]
+
+\e[32mArguments:\e[0m
+
+  [None | help]: show this usage help
+
+  [TAB COMPLETION]: run given shell plugin
+
+    custom = custom plugins in custom plugin location
+    repo   = repository plugins in repository location
+
+  [args]: arguments to plugin
 
 \e[32mExamples:\e[0m
 
-  \e[37;2m# Execute a repository plugin in '${_repo}'\e[0m
+  \e[37;2m# See this usage help\e[0m
+  $ $global_usage help
+
+  \e[37;2m# The output of tab completion\e[0m
+  $ $global_usage \\\t\\\t
+    custom/billing/invoice.bash   help                          repo/timew_to_timeclock.bash
+    custom/billing/manage.bash    repo/example.bash
+
+  \e[37;2m# Execute a repository shell plugin in '${_repo}'\e[0m
   $ $global_usage repo${global_arg_delim_1}example.bash \"I'm in repo\"
 
-  \e[37;2m# Execute a custom plugin in '${_custom}'\e[0m
+  \e[37;2m# Execute a custom shell plugin in '${_custom}'\e[0m
   $ $global_usage custom${global_arg_delim_1}example.bash \"I'm in custom\"
 "