Return the binding for command KEY in current keymaps.
KEY is a string or vector, a sequence of keystrokes.
The binding is probably a symbol with a function definition.
Normally, `key-binding' ignores bindings for t, which act as default
bindings, used when nothing else in the keymap applies; this makes it
usable as a general function for probing keymaps. However, if the
optional second argument ACCEPT-DEFAULT is non-nil, `key-binding' does
recognize the default bindings, just as `read-key-sequence' does.
Like the normal command loop, `key-binding' will remap the command
resulting from looking up KEY by looking up the command in the
current keymaps. However, if the optional third argument NO-REMAP
is non-nil, `key-binding' returns the unmapped command.
If KEY is a key sequence initiated with the mouse, the used keymaps
will depend on the clicked mouse position with regard to the buffer
and possible local keymaps on strings.
If the optional argument POSITION is non-nil, it specifies a mouse
position as returned by `event-start' and `event-end', and the lookup
occurs in the keymaps associated with it instead of KEY. It can also
be a number or marker, in which case the keymap properties at the
specified buffer position instead of point are used. (fn KEY &optional ACCEPT-DEFAULT NO-REMAP POSITION)