Template:cpp/error/error code/navbar content

From cppreference.com

Member functions
error_code::error_code
error_code::operator=
error_code::assign
Modifiers
error_code::clear
Observers
error_code::value
error_code::category
error_code::default_error_condition
error_code::message
error_code::operator bool
Non-member functions
operator==operator!=operator<operator<=> (until C++20)(until C++20)(C++20)
operator<<
Helper classes
is_error_code_enum
hash<std::error_code>