fix eat of typing char after completion done

[zbinlin]

When using typescript-language-server, in content Math.ab|, if you type <C-X><C-o> for omni completion, it will be completed with s. Then, the content will become Math.abs|. If you continue type (, the ( will be removed. Also, if type <CR>, a new line will be added, resulting in Math.abs|s\nMath.ab. This patch attempts to fix this issue.

[mattn]

Thanks. I'll look this soon

[mattn]

Thank you