Fix the issue of sections not wrapped in some contexts
Transclusion fragments with same about attributes is a very tricky
concept to handle. It does not tell where the fragments are ending.
Sections should never break in between those fragment sequences too.
A particular case where the nested sections are considered as one
single section instead of removing <section> and reapplying CX
section tags was found. Here also, transclusion context ending was
not accurately found. A scope variable is added to transclusion context
now to track and detect the ending of fragment sequences.
Example articles to test: en:Marine_life, en:Paris