First noted here: #2073 (comment)

Technically a GitHub bug, but it appears to be pretty consistent: There's an extra space at the beginning and at the end of each line.

show-whitespace should skip these spaces when rendering embedded code.

Screenshot

Live tests

https://github.com/sindresorhus/refined-github/blob/2e4a24d3957c205c7bc49525c69e1fa08593d2ca/readme.md#L107-L112

https://github.com/sindresorhus/refined-github/blob/0b40361983b362d028fac2fe0fed9486134fa41e/package.json#L1-L4