Export post title with markup

[GaryJ]

The Theme Unit Test data includes a post ​Title With Markup. However, the current exporter filters the post titles with the_title_rss, which has strip_tags hooked to it, so it always needs fixing up after importing.

The content and excerpt blocks of the export are uniquely filtered with the_content_export and the_excerpt_export, and not the_content_rss and the_excerpt_rss.

Attached is a patch which changes the exporter from using the_title_rss to a new the_title_export filter, and wraps the output in CDATA tags, as per content and export blocks.

Advantages:

• Unique filter for handling post titles during export.
• Fixes stripped tags issue.
• Filter name that is consistent with other filters in that context.
• Use of wxr_cdata() for consistency with other blocks of output in that context.

Disadvantage:

• Backwards-incompatibility - applying a filter to the_title_rss thinking it would also apply to exports would no longer work.

There are no un-skipped unit tests in place for testing the exporter so I've not included any here.

[GaryJ]

Change exporter from the_title_rss filter to the_title_export

[GaryJ]

Messy but more backwards-compatible solution

[GaryJ]

A messier but more backwards-compatible solution would be to unattach strip_tags, ent2ncr and esc_html from the_title_rss, and attach a call to wxr_cdata(), echo it, then optionally unattach it again afterwards.

Patch attached.

[stevenkword]

This directly relates to #9993 in the Feeds component and I think we are leaning towards removing the filter as well.