pg_hexedit now supports GiST, GIN, and hash indexes

I've added several enhancements to pg_hexedit, the experimental hex editor toolkit that allows you to open up raw PostgreSQL relation files with useful tags and annotations about the state and purpose of each field. The tool now supports annotations for GiST, GIN, and hash indexes, as well as sequences.

GIN "posting tree" leaf page. Compressed TIDs are in orange.