scanner: Replace #define tab with space

wayland-client-protocol.h and wayland-server-protocol.h use a tab
between the identifier and token of generated #defines for request/event
opcodes and versions. While this sometimes enables vertical alignment,
it more frequently doesn't, and leads to awkward spacing.

Replace the tab with a space, for consistency and readability.

Signed-off-by: Yong Bakos <ybakos@humanoriented.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Tested-by: Quentin Glidic <sardemff7+git@sardemff7.net>