bug(help): Fix style issues with tables in help

[tombrunet]

• Other (Provide information)
  Bug in the help. See also [BUG] Formatting issue and typo in help for element_mouseevent_keyboard  #941

This PR is related to the following issue(s):

• [BUG] Formatting issue and typo in help for element_mouseevent_keyboard  #941

Additional information can be found here:

Testing reference:

I have conducted the following for this PR:

• I validated this code in Chrome and FF
• I validated this fix in my local env
• I provided details for testing
• This PR has been reviewed and is ready for test
• I understand that the title of this PR will be used for the next release notes.

[tombrunet]

Image with mouse over of the second row:

The only help file I could find with a table is element_mouseevent_keyboard.html.

[philljenkins]

I reviewed the CSS changes, additions for table, and the new DocType in all the Help .html files

[philljenkins]

@ErickRenteria this PR can be tested by running the ruleunit testcase and displaying the Help to see the table formatted in the Help page
... equal-access/accessibility-checker-engine/test/v2/checker/accessibility/rules/element_mouseevent_keyboard_ruleunit/Events-invalidNoMouseRequired.svg

Also note that building all PR's now generates a Rule listing artifact in the Actions (see screenshot) that lists the rules, showing the new WCAG 2.2 (A, AA) option and the new WCAG 2.2 rules, such as

2.4.11 Focus Not Obscured (Minimum) [AA]
When an element receives focus, it is not entirely covered by other content.
element_tabbable_unobscured: When an element receives focus, it is not entirely covered by other content

[ErickRenteria]

Under review