Verify that A and H keyboard shortcuts do not require passthrough mode

[lyzadanger]

On screen readers other than VoiceOver, the A and H keys for annotating and highlighting respectively do not work without entering passthrough mode. This is not an ideal user experience and not obvious to the screen reader users.

Matt D says:

Important to note that this ^ is not an issue specific to Hypothesis, but to any web app requiring text selection.

[lyzadanger]

Assigning myself for the moment. My first plan is to check in with @mattdricker on this.

[robertknight]

For NVDA using the A / H shortcuts to create an annotation or highlight does require using one of NVDA's methods to pass keys through to the screen reader:

• Press NVDA+F2 to enable passing through the next key, then press A / H OR
• Toggle single-letter navigation on/off in NVDA using NVDA + Shift + Space

This issue is not specific to Hypothesis. From the NVDA documentation:

Some web applications such as Gmail, Twitter and Facebook use single letters as shortcut keys. If you want to use these while still being able to use your cursor keys to read in browse mode, you can temporarily disable NVDA's single letter navigation keys. To toggle single letter navigation on and off for the current document, press NVDA+shift+space.

See https://www.nvaccess.org/files/nvda/documentation/userGuide.html#SingleLetterNavigation.

Regarding this comment:

This is not an ideal user experience and not obvious to the screen reader users.

On the basis that this issue applies to major web properties and is explicitly mentioned in NVDA's documentation, I think it may be reasonable to assume that screen reader users are aware of the need for pass through. However, I can see that it might be more convenient if we also had a shortcut which didn't conflict with single-letter key navigation.

[dwhly]

However, I can see that it might be more convenient if we also had a shortcut which didn't conflict with single-letter key navigation.

Ok