Add 'reverse_fields' TOML config item to documentation. (#62)

Co-authored-by: David Antliff <david.antliff@sqc.com.au>

Author: DavidAntliff

README.md

@@ -39,10 +39,10 @@ user_template_dir = "path/to/dir/"
 user_static_dir = "path/to/dir/"
 extra_doc_properties = ["list", "of", "properties"]
 generate_source_links = false
+reverse_fields = false
 ```
 
 
-
 ## Reference
 
 ### `HTMLExporter(**kwargs)`
@@ -63,8 +63,8 @@ Constructor for the HTML exporter class
     * Additional context variables to load into the template namespace.
 * `show_signals`
     * Show signal components. Default is False
-* `reverse-fields`
-    * Show fields in reverse order (LSB to MSB). Default is False
+* `reverse_fields`
+    * Show fields in reverse order (LSB to MSB). Default is False (MSB to LSB).
 * `extra_doc_properties`
     * List of properties to explicitly document.