pc elements in xliff 2.1 exports are not correctly nested in conjunction with TrackChanges Markup

If one opening tag is moved, in xliff 2.1 markup it is encapsulated in mrk-Tags for TrackChanges markup both: In the position, where it is deleted and where it is added.

This leads to wrong nesting, since only the opening tag is encapsulated.

Therefore the opening pc-tag must be replaced with an sc-tag and the closing pc-tag must be replaced with an ec tag, that references to the sc-tag with startRef-Attribute.