runtime(doc): remove non-existent parameter in shift-command (vim/vim#13626)
The variant with the {count} parameter is explained in the next item.
2103a56eab
N/A patches:
vim-patch:9.0.2150: Using int for errbuflen in option funcs
vim-patch:3f7855a6123c
Co-authored-by: Roy Orbitson <Roy-Orbison@users.noreply.github.com>