Remove references to flag HelpProviders

As these don't appear to be currently supported, remove references
to them working (from main README)

README.md

@@ -8,39 +8,40 @@
 
 <!-- MarkdownTOC autolink="true" style="ordered" indent="    " -->
 
-1. [Introduction](#introduction)
-1. [Help](#help)
-    1. [Help as a user of a Kong application](#help-as-a-user-of-a-kong-application)
-    1. [Defining help in Kong](#defining-help-in-kong)
-        1. [Showing the _command_'s detailed help](#showing-the-commands-detailed-help)
-        1. [Showing an _argument_'s detailed help](#showing-an-arguments-detailed-help)
-        1. [Showing a _flag_'s detailed help](#showing-a-flags-detailed-help)
-1. [Command handling](#command-handling)
-    1. [Switch on the command string](#switch-on-the-command-string)
-    1. [Attach a `Run(...) error` method to each command](#attach-a-run-error-method-to-each-command)
-1. [Hooks: BeforeResolve\(\), BeforeApply\(\), AfterApply\(\) and the Bind\(\) option](#hooks-beforeresolve-beforeapply-afterapply-and-the-bind-option)
-1. [Flags](#flags)
-1. [Commands and sub-commands](#commands-and-sub-commands)
-1. [Branching positional arguments](#branching-positional-arguments)
-1. [Positional arguments](#positional-arguments)
-1. [Slices](#slices)
-1. [Maps](#maps)
-1. [Custom named decoders](#custom-named-decoders)
-1. [Supported field types](#supported-field-types)
-1. [Custom decoders \(mappers\)](#custom-decoders-mappers)
-1. [Supported tags](#supported-tags)
-1. [Plugins](#plugins)
-1. [Dynamic Commands](#dynamic-commands)
-1. [Variable interpolation](#variable-interpolation)
-1. [Validation](#validation)
-1. [Modifying Kong's behaviour](#modifying-kongs-behaviour)
-    1. [`Name(help)` and `Description(help)` - set the application name description](#namehelp-and-descriptionhelp---set-the-application-name-description)
-    1. [`Configuration(loader, paths...)` - load defaults from configuration files](#configurationloader-paths---load-defaults-from-configuration-files)
-    1. [`Resolver(...)` - support for default values from external sources](#resolver---support-for-default-values-from-external-sources)
-    1. [`*Mapper(...)` - customising how the command-line is mapped to Go values](#mapper---customising-how-the-command-line-is-mapped-to-go-values)
-    1. [`ConfigureHelp(HelpOptions)` and `Help(HelpFunc)` - customising help](#configurehelphelpoptions-and-helphelpfunc---customising-help)
-    1. [`Bind(...)` - bind values for callback hooks and Run\(\) methods](#bind---bind-values-for-callback-hooks-and-run-methods)
-    1. [Other options](#other-options)
+- [Kong is a command-line parser for Go](#kong-is-a-command-line-parser-for-go)
+  - [Introduction](#introduction)
+  - [Help](#help)
+    - [Help as a user of a Kong application](#help-as-a-user-of-a-kong-application)
+    - [Defining help in Kong](#defining-help-in-kong)
+      - [Showing the _command_'s detailed help](#showing-the-commands-detailed-help)
+      - [Showing an _argument_'s detailed help](#showing-an-arguments-detailed-help)
+  - [Command handling](#command-handling)
+    - [Switch on the command string](#switch-on-the-command-string)
+    - [Attach a `Run(...) error` method to each command](#attach-a-run-error-method-to-each-command)
+  - [Hooks: BeforeResolve(), BeforeApply(), AfterApply() and the Bind() option](#hooks-beforeresolve-beforeapply-afterapply-and-the-bind-option)
+  - [Flags](#flags)
+  - [Commands and sub-commands](#commands-and-sub-commands)
+  - [Branching positional arguments](#branching-positional-arguments)
+  - [Positional arguments](#positional-arguments)
+  - [Slices](#slices)
+  - [Maps](#maps)
+  - [Nested data structure](#nested-data-structure)
+  - [Custom named decoders](#custom-named-decoders)
+  - [Supported field types](#supported-field-types)
+  - [Custom decoders (mappers)](#custom-decoders-mappers)
+  - [Supported tags](#supported-tags)
+  - [Plugins](#plugins)
+  - [Dynamic Commands](#dynamic-commands)
+  - [Variable interpolation](#variable-interpolation)
+  - [Validation](#validation)
+  - [Modifying Kong's behaviour](#modifying-kongs-behaviour)
+    - [`Name(help)` and `Description(help)` - set the application name description](#namehelp-and-descriptionhelp---set-the-application-name-description)
+    - [`Configuration(loader, paths...)` - load defaults from configuration files](#configurationloader-paths---load-defaults-from-configuration-files)
+    - [`Resolver(...)` - support for default values from external sources](#resolver---support-for-default-values-from-external-sources)
+    - [`*Mapper(...)` - customising how the command-line is mapped to Go values](#mapper---customising-how-the-command-line-is-mapped-to-go-values)
+    - [`ConfigureHelp(HelpOptions)` and `Help(HelpFunc)` - customising help](#configurehelphelpoptions-and-helphelpfunc---customising-help)
+    - [`Bind(...)` - bind values for callback hooks and Run() methods](#bind---bind-values-for-callback-hooks-and-run-methods)
+    - [Other options](#other-options)
 
 <!-- /MarkdownTOC -->
 
@@ -134,7 +135,7 @@ Help is automatically generated from the command-line structure itself,
 including `help:""` and other tags. [Variables](#variable-interpolation) will
 also be interpolated into the help string.
 
-Finally, any command, argument, or flag type implementing the interface
+Finally, any command, or argument type implementing the interface
 `Help() string` will have this function called to retrieve more detail to
 augment the help tag. This allows for much more descriptive text than can
 fit in Go tags.  [See _examples/shell/help](./_examples/shell/help)
@@ -193,13 +194,6 @@ Flags:
       --flag    Regular flag help
 ```
 
-#### Showing a _flag_'s detailed help
-
-> **TODO** (not known how to elicit this behaviour)
-
-Neither `go run ./main.go --help --flag` nor `go run ./main.go --flag --help` appear to work
-
-
 ## Command handling
 
 There are two ways to handle commands in Kong.