sh(1): fix home/del key on mobaxterm env

For $reason mobaxterm default on sending unusual sequence from home/del
key, which makes libedit unabel to catch them and bind them correctly.

mobaxterm seems popular on the windows environment, so add proper
keybinding to default shrc configuration so it works out of box.

Reported by: lme

(cherry picked from commit f3aad18d5e57328469be0e3be9e17d7bc48e6822)