v2.2.5: more read path info

Changes from the previous version include

- feat: add some tsquery constants
- feat: detail YB read path plans
- feat: detail gdb observing required/additional
- feat: expand read path extended
- fix: add read path step to update advancePast
- fix: note startScan before "Put a breakpoint"
- refactor: detail required/additional for gdb

v2.2.4: draft before nulls design meeting

Changes from the previous version include

- feat: add note that advanced material is pg not yb
- feat: add nulls docdb encoding section
- refactor: rm examples from constants section
- refactor: split off to multicolumn subsection

v2.2.3: some changes

Changes from the previous version include

- feat: add array strategy constants
- feat: add null category constants
- feat: add null category examples
- feat: add search mode examples
- fix: add missing fox key in read-path-extended
- refactor: improve ps command to have kstart_time
- refactor: mv breakpoint later for more info

v2.2.2: more polishing

Address a comment from the second meeting (all of YQL), and do other
misc changes.  Changes from the previous version include

- feat: add footnote refs to ginhandler amroutine
- feat: add single column example for tsvector docdb
- feat: expand on read path extended
- feat: show simplified tsvector docdb encoding

v2.2.1: address first design meeting comments

Address comments from the first design meeting.  Changes from the
previous version include

- feat: note DELETEs and UPDATEs handling
- fix: correct the design for multicolumn index
- fix: detail the problems and potential solutions for fixed schemas
- fix: make sure jsonb_full_ops encoding avoids ambiguity with keys
- fix: remove a bad backslash before percent
- fix: typo operator @? to @@

v2.2: Draft before first design meeting

The draft to be used during the first design meeting with DocDB people.
Changes from the previous version include

- docs: note linkcolor option in README
- feat: add columns-to-keys table
- feat: add in type, key type to opclasses table
- feat: add jsonb_full_ops opclass
- feat: add search mode constants
- feat: rewrite docdb encoding sections
- feat: show how two opclasses can be used
- fix: correct an array operator from `@` to `<@`
- fix: correct array `=` operator example to not do size-based recheck
- fix: recommend viewing `nuserentries` over `nentries` in GDB
- refactor: change some links to footnotes
- refactor: split operator translations to a separate section

v2.1.1: add toc and gdb guide

Changes from the previous version include

- build: add make clean recipe
- feat: add GDB guides
- feat: add option to toggle link coloring
- feat: add table of contents

v2.1: First public draft

The draft when the source code goes public.  Changes from the previous
version include

- feat: add tables describing each operator
- feat: dark mode option
- fix: correct the translation for the array equality operator
- fix: get rid of inconsistent uses of `ik` and `pk`
- fix: mark the DocDB section with lots of todos
- refactor: move jsonb opclass encoding details to the DocDB section
- refactor: remove formality on recheck primitive since it's too broad
- refactor: split up source into more files