options: drop --opt:subopt option names

For all suboptions, "flat" options were available by separating the
parent option and the sub option with ":", e.g. "--rawvideo:w=123". Drop
this syntax and use "-" as separator. This means even suboptions are
available as normal options now, e.g. "--rawvideo-w=123". The old syntax
doesn't work anymore.

Note that this is completely separate from actual suboptions. For
example, "-rawvideo w=123:h=123" still works. (Not that this syntax is
worth supporting, but it's needed anyway, for for other things like vf
and vo suboptions.)

As a consequence of this change, we also have to add new "no-" prefixed
options for flag suboptions, so that "--no-input-default-bindings"
works. ("--input-no-default-bindings" also works as a consequence of
allowing "-input no-default-bindings" - they are handled by the same
underlying option.)

For --input, always use the full syntax in the manpage. There exist
suboptions other than --input (like --tv, --rawvideo, etc.), but since
they might be handled differently in the future, don't touch these yet.

M_OPT_PREFIXED becomes the default, so remove it. As a minor unrelated
cleanup, get rid of M_OPT_MERGE too and use the OPT_SUBSTRUCT() macro in
some places.

Unrelated: remove the duplicated --tv:buffersize option, fix a typo in
changes.rst.

1 files changed, 1 insertions, 1 deletions

diff --git a/video/out/vo_image.c b/video/out/vo_image.c
index 7188abf9b0..95caf2611f 100644
--- a/video/out/vo_image.c
+++ b/video/out/vo_image.c
@@ -196,7 +196,7 @@ const struct vo_driver video_out_image =
         .colorspace = MP_CSP_DETAILS_DEFAULTS,
     },
     .options = (const struct m_option[]) {
-        OPT_SUBSTRUCT(opts, image_writer_conf, M_OPT_MERGE),
+        OPT_SUBSTRUCT("", opts, image_writer_conf, 0),
         OPT_STRING("outdir", outdir, 0),
         {0},
     },