Update documentation to showcase SS01 which is single story g

Upon inspecting the font, there is already a single story g, which is less distracting and enhances the overall appearance of the font. Again, it's a personal opinion. But there might be people like me, and it would be nice to showcase it in the documentation.

Attaching an image.

Most of the editors support OTF features, like just enabling ss01

And for editors like JetBrains, people can build the font like this.

``` shell
╰─❯ pyftfeatfreeze -n -v -f 'ss01' /Users/pratyush/Desktop/GoogleSansCode-BoldItalic.otf /Users/pratyush/Desktop/out/GoogleSansCode-BoldItalic.otf
```

More details about the font freezer.
https://github.com/twardoch/fonttools-opentype-feature-freezer