Ingestion: NLP4CALL

[anthology-assist]

1. [x] In the Github sidebar, add the PR to work items and the current milestone
2. [x] In the Github sidebar, under "Development", make sure to link to the corresponding issue
3. [x] Make sure the branch is merged with the latest master branch
4. [x] Ensure that there are editors listed in the <meta> block
5. [x] For workshops, add a <venue>ws</venue> tag to its meta block
6. [ ] For workshops, add a backlink from the main event's <event> block
7. [ ] Add events to their relevant SIGs
8. [x] Look at the venue listing for prior years, and ensure that the new volume titles are consistent. You can do this by clicking on the venue name from a paper page, which will take you to the vendor listing.
9. [x] Navigate to the event page preview (e.g., https://preview.aclanthology.org/icnlsp-ingestion/events/icnlsp-2021/), and page through, to see if there are any glaring mistakes
10. [x] Skim through the complete listing, looking for mis-parsed author names.
11. [x] Download the frontmatter and verify that the table of contents matches at least three randomly-selected papers
12. [x] Download 3–5 PDFs (including the first and last one) and make sure they are correct (title, authors, page numbers).