This aligns the man page with the usage output of the tool.

Signed-off-by: Christian Amsüss <chrysn@fsfe.org>
---

This confused me a bit when I first read the man page (why could a
read-only snapshot not be assigned to a qgroup), but experimentation and
looking at --help indicate that the mutual exclusivity of those options
in the man page was most likely due to an editing error when the option
was introduced.

 Documentation/btrfs-subvolume.asciidoc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/btrfs-subvolume.asciidoc b/Documentation/btrfs-subvolume.asciidoc
index d8c414fd..89c3c263 100644
--- a/Documentation/btrfs-subvolume.asciidoc
+++ b/Documentation/btrfs-subvolume.asciidoc
@@ -207,7 +207,7 @@ rootid of the subvolume.
 -u|--uuid::::
 UUID of the subvolume.
 
-*snapshot* [-r|-i <qgroupid>] <source> <dest>|[<dest>/]<name>::
+*snapshot* [-r] [-i <qgroupid>] <source> <dest>|[<dest>/]<name>::
 Create a snapshot of the subvolume <source> with the
 name <name> in the <dest> directory.
 +
-- 
2.27.0

-- 
We are dreamers, shapers, singers, and makers.
  -- Elric