Emacs keyboard shortcuts only support the left control and left alt keys

[bryce-carson]

Keyboarding ergonomically requires a typist to use a modifier key on the opposing side of the keyboard (if the alphanumeric key to be modified is the 4 key, the right shift key should be used). For example, with the Emacs keyboard shortcuts enabled a user must currently type M-f to issue the forward-word command with the left alt key, which is not ergonomic. The right alt key and the right control key are unrecognized.