Parameter name, specified as a string or a character vector.
The name must be a valid token, containing only characters defined in
RFC
7230 Field Value Components, section 3.2.6. To set an unnamed
parameter, use "" or ''.
Name matching is not case-sensitive, but value is
case-sensitive. If name matches an existing parameter,
but with a different case, then the parameter name is changed to the case of
the specified name.
If there are multiple matching parameters, then all are changed to
value.