Update zenkaku title in README

Remove redundant English title from documentation header.

Author: mkobayashime

README.md

@@ -61,7 +61,7 @@ Put current timestamp to the `t` query parameter
 
 Reopen currently playing music as video in normal YouTube
 
-### [入力中の値を全角に変換 Convert input text from Hankaku to Zenkaku](https://raw.githubusercontent.com/mkobayashime/bookmarklets/main/dist/zenkaku.js)
+### [入力中の値を全角に変換](https://raw.githubusercontent.com/mkobayashime/bookmarklets/main/dist/zenkaku.js)
 
 フォームなどで入力欄に入力中の値のうち、半角の数値などを全角に変換します