refactor(completion): clean up popup scroll API

lua/lsp/completion/popup.lua

@@ -135,15 +135,7 @@ function Popup:dispatch_resolve(client, item, ft, pum, word, buf)
     end
 end
 
----@param direction string single-line scroll keycode (<C-e> or <C-y>)
-function Popup:scroll_line(direction)
-    self:scroll(direction, 1)
-end
-
----@param direction string
-function Popup:scroll_half(direction)
-    self:scroll(direction, HALF_HEIGHT)
-end
+Popup.HALF_PAGE = HALF_HEIGHT
 
 ---@param content string
 ---@param pum ow.lsp.completion.Pum
@@ -209,14 +201,16 @@ function Popup:render(content, pum, width)
     self:update_indicators()
 end
 
----@param direction string
+---@param direction "up" | "down"
 ---@param count integer
 function Popup:scroll(direction, count)
     if not self:is_visible() then
         return
     end
+    local key = direction == "down" and vim.keycode("<C-e>")
+        or vim.keycode("<C-y>")
     vim.api.nvim_win_call(self.winid, function()
-        vim.cmd.normal({ args = { count .. direction }, bang = true })
+        vim.cmd.normal({ args = { count .. key }, bang = true })
     end)
     self:update_indicators()
 end