js-mode: Load the command json-reformat-region
on-screen-mode: Enable globally and use the minor mode key prefix
Remove ejmr/toggle-read-only-viewing and its key chord

For some reason it doesn’t work and I have not used it enough honestly
to justify the effort to fix it.
Key Chord: Bind ‘$$’ to ispell-buffer

The binding is meant as a mnemonic for the M-$ command.