Allow whitespace between the :substitute command and its pattern
argument. Although unusual, it is supported and there are examples in
the wild.
Match Vi compatible :substitute commands like :s\/{string}/. See :help
E1270.
fixes: #14920closes: #14923
Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
