Change cmp.mapping.scroll_docs to <C-b> and <C-f> for scroll up and down

respectively

init.lua

@@ -680,8 +680,8 @@ require('lazy').setup({
           ['<C-p>'] = cmp.mapping.select_prev_item(),
 
           -- scroll [u]p and [d]own the documentation window
-	  ["<C-u>"] = cmp.mapping.scroll_docs(-4),
-	  ["<C-d>"] = cmp.mapping.scroll_docs(4),
+          ['<C-b>'] = cmp.mapping.scroll_docs(-4),
+          ['<C-f>'] = cmp.mapping.scroll_docs(4),
 
           -- Accept ([y]es) the completion.
           --  This will auto-import if your LSP supports it.