Proposal of additional characters used in Written Cantonese

There are frequently 'issues' requesting the addition of some glyphs (cf. [240](https://github.com/adobe-fonts/source-han-sans/issues/240), [228](https://github.com/adobe-fonts/source-han-sans/issues/228), [231](https://github.com/adobe-fonts/source-han-sans/issues/231)). They are frequently based on gut feelings or arbitrary selections. Here I'm hoping to be at least tiniest bit more scientific in such a discussion.

It is not a secret that the IICore2020 list of Hong Kong characters does not limit those actually in use in Written Cantonese. Luckily, now we have an up-to-date method of checking which exactly are used: Robert S. Bauer's _The ABC Cantonese-English Comprehensive Dictionary_, specifically aimed at describing the writing traditions of current Cantonese-speakers in Hong Kong. I have cross-checked the complete text of the dictionary against both the Super OTC (to determine glyphs completely missing) and the HK Subset OTF (to find out the cases where some other locality's glyphs silently serve as fallbacks). The comprehensive results (and a manually-concocted GlyphWiki-derived Hanazono Mincho-based font containing all of Tables 1&2, attached inside the .pdf) are in the file below. These is the squeeze of the main results:

**Table 1. Glyphs from Extensions B‒F absent from Source Han Sans despite usage in Written Cantonese**

I request to add the completely new glyphs for the following Unicode points, drawn in HK-style, or at least those **in bold**:

Point | Glyph | Reading
----|----|----
**U+20C32** | 𠰲 | oek2/4/6, oet2/4/6
U+216A6 | 𡚦 | hai1
U+22D15 | 𢴕 | ling1, ning1
U+259F9 | 𥧹 | dam6, tam4/5
U+265E7 | 𦗧 | dap1
**U+272F5** | 𧋵 | kwong4
**U+27685** | 𧚅 | long6, nong6
U+2B9F6 | 𫧶 | keng4
U+2BA5D | 𫩝 | ci1
**U+2BAC3** | 𫫃 | e1, nge1
U+2BAFC | 𫫼 | ngap1
**U+2BB3F** | 𫬿 | ngang2, ngang4
**U+2BB4A** | 𫭊 | wang6
**U+2BCAD** | 𫲭 | keng1
**U+2BD71** | 𫵱 | cat6
**U+2C710** | 𬜐 | lem2, lim2
**U+2C9A0** | 𬦠 | naai2
**U+2C9CA** | 𬧊 | lak1
**U+2C9EF** | 𬧯 | beu6
U+2CE33 | 𬸳 | gaan2
**U+2D25D** | 𭉝 | syu2, syu4
U+2D85A | 𭉝 | faak3

**Table 2. Glyphs outside Unicode used in Written Cantonese that can be incorporated using IDS composition**

For one or other reason, there are still 11 out-of-Unicode glyphs actively used in Cantonese. Ideally, it would be great to include those as their IDS composition, but this is not of immediate necessity.

IDS | Reading
----|----
⿸疒背 | bui6
⿰口揼 | dap6
⿰口絞 | gaau6
⿰口剋 | gwak6
⿰口乜 | met1
⿰口揖 | jaap6, ngap1
⿱弗手 | dap6
⿰口壁 | bek6
⿰扌罨 | ngap1
⿰口梃 | ting2
⿰扌熨 | tong3

**Table 3. Glyphs from URO and Extension A used in Written Cantonese and having HK forms in Source Han Sans**

For the following, a total inaction is required, except adding them to Subset OTF for HK region.

内厾咊哴岀捞捦査横歳爲盘蝲譲趸鬦鬬䁽

**Table 4. Glyphs from URO and Extension A used in Written Cantonese not having HK forms in Source Han Sans**

These require additional HK form to be drawn.

哾噖庝掕攋煈脶舗蝄㞓䭤

To conclude: the simplest and immediate course of action is adding the characters in Tables 3 and 4 to the Subset OTF for Cantonese.

[Cantonese Breakdown Chart.pdf](https://github.com/adobe-fonts/source-han-sans/files/3552065/Cantonese.Breakdown.Chart.pdf)