fix

Author: yosupo06

document_en/keywords.toml

@@ -1,4 +1,4 @@
 constraints = 'Constraints'
 complexity = 'Complexity'
 examples = 'Examples'
-info = '*The version of this document may differ from the one which is installed in AtCoder, AtCoder-installed version is [here](https://atcoder.github.io/ac-library/production/document_ja/).*'
+info = '*The version of this document may differ from the one which is installed in AtCoder, AtCoder-installed version is [here](https://atcoder.github.io/ac-library/production/document_en/).*'