Add lang query string to help URLs

[WilcoFiers]

To support DQU's localisation, axe-core's help URLs should include a language code, for example:

https://dequeuniversity.com/rules/axe/3.3/html-has-lang?lang=jp

This can be set when axe.configure() is called with a new locale.

[jeankaplansky]

@straker: This isn't a new rule, but is it something we should include in the release notes?

[jeankaplansky]

Added to release notes 10/14/2019

[padmavemulapati]

Verified this ticket, I am seeing the help URL, for language attribute is: https://dequeuniversity.com/rules/axe/3.3/html-has-lang?lang=ja (not lang=jp)
@WilcoFiers , can you please confirm that we are expecting "japanese" language , is n't it?
and from Dequeuniversity only two languages we can set and able to see the content into respective language.

[WilcoFiers]

@straker found a bug in this. The lang attribute is not added in when you build axe using:

grunt build --lang=ja

[straker]

Opened a separate issue #1861.

[padmavemulapati]

As this issue is tracking in #1861, closing this ticket