[Major]: Review PDDL2.1 and check the BNF definitions for missed feature

[Adam Green]

Link to affected page(s):

• https://nergmada.github.io/pddl-reference/reference/PDDL2.1/main.html

Proposed corrections:

• This set of pages excludes details on on timed effects e.g. (at 10 ) this needs to be corrected if the BNF in the attached paper has not be exactly replicated on the page.
• full review of the BNF defined for PDDL2.1 to check for any other missing features

References to papers with supporting information (Recommended):

• https://arxiv.org/pdf/1106.4561.pdf