Merge pull request #32098 from bfredl/multihl_group

feat(extmark): stack multiple highlight groups in `hl_group`

runtime/lua/vim/_meta/api.lua

@@ -574,6 +574,9 @@ function vim.api.nvim_buf_line_count(buffer) end
 --- - hl_group : highlight group used for the text range. This and below
 ---     highlight groups can be supplied either as a string or as an integer,
 ---     the latter of which can be obtained using `nvim_get_hl_id_by_name()`.
+---
+---     Multiple highlight groups can be stacked by passing an array (highest
+---     priority last).
 --- - hl_eol : when true, for a multiline highlight covering the
 ---            EOL of a line, continue the highlight for the rest
 ---            of the screen line (just like for diff and

runtime/lua/vim/_meta/api_keysets.lua

@@ -241,7 +241,7 @@ error('Cannot require a meta file')
 --- @field end_line? integer
 --- @field end_row? integer
 --- @field end_col? integer
---- @field hl_group? integer|string
+--- @field hl_group? any
 --- @field virt_text? any[]
 --- @field virt_text_pos? string
 --- @field virt_text_win_col? integer