Clarify that --root does not restrict filesystem access

The `--root` option only strips a prefix from template names, but its
description could be read as limiting which files the CLI reads. State
explicitly that it is not a filesystem boundary.

Author: jaylinski

bin/handlebars

@@ -65,7 +65,7 @@ var argv = parseArgs({
   },
   'r': {
     'type': 'string',
-    'description': 'Template root. Base value that will be stripped from template names.',
+    'description': 'Template root. Base value that will be stripped from template names; it does not restrict filesystem access.',
     'alias': 'root'
   },
   'p': {

spec/expected/help.menu.txt

@@ -16,7 +16,8 @@ Options:
                        multiple templates.                                                                      [string]
   -i, --string         Generates a template from the passed CLI argument.
                        "-" is treated as a special value and causes stdin to be read for the template value.    [string]
-  -r, --root           Template root. Base value that will be stripped from template names.                     [string]
+  -r, --root           Template root. Base value that will be stripped from template names; it does not restrict
+                       filesystem access.                                                                       [string]
   -p, --partial        Compiling a partial template                                                            [boolean]
   -d, --data           Include data when compiling                                                             [boolean]
   -e, --extension      Template extension.                                              [string] [default: "handlebars"]