Support for isolating formatting characters lacking in some browsers

[r12a]

This issue is applicable to all languages using a right-to-left script.

For support of bidirectional plain text, the Unicode Standard provides a number of formatting characters, which include RLI, LRI, PDI and FSI. See an explanation of how these work.

Although markup should be used most of the time in HTML pages, there are parts of an HTML document that don't support markup, such as the title element and title, alt, and other attributes. These characters can be necessary for managing inline runs of such text.

For more details, see this GitHub issue, which is being used to track this gap.

[r12a]

The first comment in this issue contains text that will automatically appear in one or more gap-analysis documents as a subsection with the same title as this issue. Any edits made to that comment will be immediately available in the document. Proposals for changes or discussion of the content can be made in comments below this point.

Relevant gap analysis documents include:
Arabic & Persian • Adlam • Hebrew • Kashmiri • N'Ko • Uighur

[xfq]

Related browser bug: https://bugs.webkit.org/show_bug.cgi?id=130823