The `Matcher` in `merge_subtokens()` returns all possible subsequences
of `subtok`, so for sequences of two or more subtoks it's necessary to
filter the matches so that the retokenizer is only merging the longest
matches with no overlapping spans.
* Add work in progress
* Update analysis helpers and component decorator
* Fix porting of docstrings for Python 2
* Fix docstring stuff on Python 2
* Support meta factories when loading model
* Put auto pipeline analysis behind flag for now
* Analyse pipes on remove_pipe and replace_pipe
* Move analysis to root for now
Try to find a better place for it, but it needs to go for now to avoid circular imports
* Simplify decorator
Don't return a wrapped class and instead just write to the object
* Update existing components and factories
* Add condition in factory for classes vs. functions
* Add missing from_nlp classmethods
* Add "retokenizes" to printed overview
* Update assigns/requires declarations of builtins
* Only return data if no_print is enabled
* Use multiline table for overview
* Don't support Span
* Rewrite errors/warnings and move them to spacy.errors
<!--- Provide a general summary of your changes in the title. -->
## Description
* tidy up and adjust Cython code to code style
* improve docstrings and make calling `help()` nicer
* add URLs to new docs pages to docstrings wherever possible, mostly to user-facing objects
* fix various typos and inconsistencies in docs
### Types of change
enhancement, docs
## Checklist
<!--- Before you submit the PR, go over this checklist and make sure you can
tick off all the boxes. [] -> [x] -->
- [x] I have submitted the spaCy Contributor Agreement.
- [x] I ran the tests, and all new and existing tests passed.
- [x] My changes don't require a change to the documentation, or if they do, I've added all required information.
