(PDK-408) Explain PowerShell escaping for -- on bundle

PowerShell evaluates '--' itself and doesn't pass it on to the pdk
function. The backtick stops PowerShell from further argument parsing
and saves the double dash from being gobbled up.

To make it easier to discover by windows users, this also changes the
usage, when run on windows.

lib/pdk/cli/bundle.rb

@@ -2,10 +2,19 @@
 module PDK::CLI
   @bundle_cmd = @base_cmd.define_command do
     name 'bundle'
-    usage _('bundle -- [bundler_options]')
+    if Gem.win_platform?
+      usage _('bundle `-- [bundler_options]')
+    else
+      usage _('bundle -- [bundler_options]')
+    end
     summary _('(Experimental) Command pass-through to bundler')
-    description _('[experimental] For advanced users, pdk bundle runs arbitrary commands in the bundler environment that pdk manages.' \
-      'Careless use of this command can lead to errors that pdk can\'t help recover from.')
+    description _(<<-EOF
+[experimental] For advanced users, pdk bundle runs arbitrary commands in the bundler environment that pdk manages.
+Careless use of this command can lead to errors that pdk can't help recover from.
+
+Note that for PowerShell the '--' needs to be escaped using a backtick: '`--' to avoid it being parsed by the shell.
+EOF
+                 )
 
     be_hidden