Clarify how other browsers handle the BSS key

[dotproto]

Chrome stopped logging a warning when the browser_specific_settings key is present in an extensions' manifest. This PR updates the note in our add-on ID docs to clarify Chrome and Safari behavior when parsing this object.

Fixes #2126

[rebloor]

@dotproto I'm wondering whether we need to re-factor this content to make clear that this applies to both manifest V2 and V3 (where you have to specify an ID and therefore include browser_specific_settings). In addition, we should probably mention this in the cross browser discussion e.g. https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Build_a_cross_browser_extension#manifest_keys

[dotproto]

@rebloor are we good to merge this change?

[rebloor]

@dotproto if you're happy that we don't need to do anything re-my comment, then yes.

I'm wondering whether we need to re-factor this content to make clear that this applies to both manifest V2 and V3 (where you have to specify an ID and therefore include browser_specific_settings). In addition, we should probably mention this in the cross-browser discussion e.g., https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Build_a_cross_browser_extension#manifest_keys

[dotproto]

Ah, sorry I overlooked that message. Yes, I agree that a refactor would be ideal. Let's land this change and address the refactor in a separate PR. I'll create an issue for that in a moment.