Add 'title' to buttons that includes info about the element for uniqueness

[Kristina Hoeppner]

Many buttons (and some links) in Mahara are in tables or lists, e.g. on the institution settings page, in web services, on 'Shared by me'. A screen reader only reads the following for exmaple:
- Edit
- Edit
- Edit

and thus can't differentiate whether the first 'Edit' is for page 'Test' or 'Learning' etc.

We should uniquely identify these. Some of the buttons already do that well, e.g. Admin menu -> Web services -> External apps. Even sighted people see a title for the button that includes the element on which the action is performed.

On Admin menu -> Institutions -> Settings the buttons have alt text, but no title. The title would bring up the 'tooltip' for sighted people and thus make it clearer what the button does that only has an icon but no text.

On Admin menu -> Extensions -> SmartEvidence, the buttons have a generic screenreader only text.

We should therefore have the same behaviour for every button in Mahara and add that helper text to identify the elements on which the actions are performed correctly. Check with the accessibility team what should be used to help both sighted and non-sighted people.

My current preference is to make sure that on hover a button displays the title rather than only making that information available to screen readers when we have a list of items. Whether such a title is sufficient for screen readers or whether we also need 'alt' or special screen reader tags will need to be decided based on accessibility best practices.

Before making any changes, please propose the plan going forward as there are lots of places in Mahara that would need to be changed.

A recent example where we've gone with a tooltip instead of aria labels is bug 1489259 because then both sighted and non-sighted people benefit.