Improve error message for creating token REST API

On using the REST API for creating a token, the error message obtained should be a gender-neutral pronoun. 

Here's the current message :

jfrog rt curl -XPOST /api/security/token -d "username=sample-service" -d "scope=member-of-groups:security-group"
{
"error" : "invalid_request",
"error_description" : "User prasanna can only create user token for himself (requested: sample-service)"

Need to change it to :
User prasanna can only create user token(s) for themselves