deduplicate_call_seq has a bug that skips call-seq for methods where the
alias is a prefix of the method name. For example, if the alias name is
"each" and the current method name is "each_line", then
deduplicate_call_seq will skip all call-seq for "each_line" since it
will believe that it is for the alias.
https://github.com/ruby/rdoc/commit/1148988ccc