patch 8.2.3743: ":sign" can add a highlight group without a name Commit: https://github.com/vim/vim/commit/5e18ccc60bdddc4aa39ab039f1a7c918f29e67ce Author: Bram Moolenaar <Bram@vim.org> Date: Sun Dec 5 13:02:50 2021 +0000 patch 8.2.3743: ":sign" can add a highlight group without a name Problem: ":sign" can add a highlight group without a name. Solution: Give an error if the group name is missing. (closes https://github.com/vim/vim/issues/9280)

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>f+0&#ffff4012|o@1| +0&#ffffff0|2| @64
|f+0&#ffff4012|o@1| +0&#ffffff0|3| @64
|f+0&#ffff4012|o@1| +0&#ffffff0|4| @64
|f+0&#ffff4012|o@1| +0&#ffffff0|5| @64
|f+0&#ffff4012|o@1| +0&#ffffff0|6| @64
|f+0&#ffff4012|o@1| +0&#ffffff0|7| @64
|f+0&#ffff4012|o@1| +0&#ffffff0|8| @64
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