Add code documentation via JSDoc

[Pomax]

https://jsdoc.app/ although it looks shit on its own so let's use https://github.com/SoftwareBrothers/better-docs to make sure that part's clean.

A docs tasklist

simple

• [ ] OS/2
• [ ] SVG
• [ ] head
• [ ] hhea
• [ ] hmtx
• [ ] maxp
• [ ] name
• [ ] post

cmap

• [ ] CMAP
  • [ ] subtable 0
  • [ ] subtable 2
  • [ ] subtable 4
  • [ ] subtable 6
  • [ ] subtable 8
  • [ ] subtable 10
  • [ ] subtable 12
  • [ ] subtable 13
  • [ ] subtable 14

advanced

• [ ] BASE
• [ ] GDEF
• [ ] GPOS
  • [ ] lookup 1
  • [ ] lookup 2
  • [ ] lookup 3
  • [ ] lookup 4
  • [ ] lookup 5
  • [ ] lookup 6
  • [ ] lookup 7
  • [ ] lookup 8
  • [ ] lookup 9
• [ ] GSUB
  • [ ] lookup 1
  • [ ] lookup 2
  • [ ] lookup 3
  • [ ] lookup 4
  • [ ] lookup 5
  • [ ] lookup 6
  • [ ] lookup 7
  • [ ] lookup 8
• [ ] JSTF
• [ ] MATH

bitmap

• [ ] CBDT
  • [ ] format17
  • [ ] format18
  • [ ] format19
• [ ] CBLC
• [ ] EBDT
  • [ ] format1
  • [ ] format2
  • [ ] format3
  • [ ] format4
  • [ ] format5
  • [ ] format6
  • [ ] format7
  • [ ] format8
  • [ ] format9
• [ ] EBLC
• [ ] EBSC
• [ ] sbix

cff

• [ ] CFF
• [ ] CFF2
• [ ] VORG

color

• [ ] COLR
• [ ] CPAL

other

• [ ] DSIG
• [ ] LTSH
• [ ] MERG
• [ ] PCLT
• [ ] VDMX
• [ ] hdmx
• [ ] kern
• [ ] meta
• [ ] vhea
• [ ] vmtx

ttf

• [ ] cvt
• [ ] fpgm
• [ ] gasp
• [ ] glyf
• [ ] loca
• [ ] prep

variation

• [ ] HVAR
• [ ] MVAR
• [ ] STAT
• [ ] VVAR
• [ ] avar
• [ ] cvar
• [ ] fvar
• [ ] gvar