ApiHelp: Add directionality to various things that are likely English-like

ApiHelp: Add directionality to various things that are likely English-like

This follows up I28e8e0cb with the other things identified during review
of that patch.

Added dir="ltr" to:
* Module names in the linktrail
* Non-internationalized extension names
* SPDX license tags
* Help URLs
* Parameter names
* Module names in the list of values for a submodule-type parameter
* Value names when using message-per-value documentation
* Example URLs

Added dir="auto" to:
* List of values for enumerated-type parameters
* Default value for parameters

Change-Id: Ie3c08ec604e1796629912fa16e6db4ae3fdce72e