Add extmark inline feature detection

lua/cmp/view/ghost_text_view.lua

@@ -9,7 +9,17 @@ local ghost_text_view = {}
 
 ghost_text_view.ns = vim.api.nvim_create_namespace('cmp:GHOST_TEXT')
 
-local has_inline = vim.fn.has('nvim-0.10') == 1
+local has_inline, msg = (function()
+  return pcall(function()
+    local id = vim.api.nvim_buf_set_extmark(0, ghost_text_view.ns, 0, 0, {
+      virt_text = { { ' ', 'Comment' } },
+      virt_text_pos = 'inline',
+      hl_mode = 'combine',
+      ephemeral = true,
+    })
+    vim.api.nvim_buf_del_extmark(0, ghost_text_view.ns, id)
+  end)
+end)()
 
 ghost_text_view.new = function()
   local self = setmetatable({}, { __index = ghost_text_view })