doc: readme: use import for cmp example (#115)

README.md

@@ -147,8 +147,8 @@ cmp.setup {
     -- You must set mapping if you want.
     mapping = {
         ["<tab>"] = cmp.mapping(function(fallback)
-            if require('neogen').jumpable() then
-                require('neogen').jump_next()
+            if neogen.jumpable() then
+                neogen.jump_next()
             else
                 fallback()
             end
@@ -157,8 +157,8 @@ cmp.setup {
             "s",
         }),
         ["<S-tab>"] = cmp.mapping(function(fallback)
-            if require('neogen').jumpable(true) then
-                require('neogen').jump_prev()
+            if neogen.jumpable(true) then
+                neogen.jump_prev()
             else
                 fallback()
             end