Patching Iosevka breaks some subtables
#### 🗹 Requirements

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#### 🎯 Subject of the issue

```
Done with Patch Sets, generating font...
WARNING: Have only minimal naming information, check resulting name. Maybe specify --makegroups 0
Lookup subtable contains unused glyph POWER making the whole subtable invalid
Lookup subtable contains unused glyph POWER making the whole subtable invalid
Lookup subtable contains unused glyph POWER making the whole subtable invalid
Lookup subtable contains unused glyph POWER making the whole subtable invalid
Lookup subtable contains unused glyph HEAVY making the whole subtable invalid
Lookup subtable contains unused glyph POWER making the whole subtable invalid
Lookup subtable contains unused glyph POWER making the whole subtable invalid
Lookup subtable contains unused glyph POWER making the whole subtable invalid
Lookup subtable contains unused glyph POWER making the whole subtable invalid
Lookup subtable contains unused glyph HEAVY making the whole subtable invalid
   Iosevka Nerd Font
   \===> 'IosevkaNerdFont-Regular.ttf'
```

Experienced behavior:
<!-- Describe issue here -->

Expected behavior:
<!-- Please do not forget to explain what you would have expected to see -->

Example symbols:
<!-- The codepoint of one or more affected symbols, or paste the text containing the issue here (no screenshot) -->

#### 🔧 Your Setup

- _Which font are you using (e.g. `Anonymice Powerline Nerd Font Complete.ttf`)?_
   - _Please give the full filename_
- _Where did you get the file from (download link, self patched, source downloaded from link...)_
   - <!-- Type your answer here -->
- _Which terminal emulator are you using (e.g. `iterm2`, `urxvt`, `gnome`, `konsole`)?_
   - <!-- Type your answer here -->
- _Are you using OS X, Linux or Windows? And which specific version or distribution?_
   - <!-- Type your answer here -->

#### ★ Screenshots (Optional)

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