Fixed nesting tabs bug

[penguoir]

When using the URL to pre-select a nested tab, activate that tab's parent tab. #5087

Proposed changes

With nested tabs, activate the parent tab if the nested tab is active through the URL.

Screenshots (if appropriate) or codepen:

Types of changes

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to change).

Checklist:

• I have read the CONTRIBUTING document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[penguoir]

Does the documentation require the use of nested tabs?

[penguoir]

Also, should there be tests for this feature?