free reports total usable RAM, not total installed memory (documentation fix needed)

man free currently says:

total   Total installed memory (MemTotal and SwapTotal in /proc/meminfo)

However, free doesn't actually report "total installed memory". On a 128GiB machine free --gibi will report about 125GiB "total installed memory" because MemTotal doesn't include bytes reserved by the kernel. According to https://www.kernel.org/doc/Documentation/filesystems/proc.txt:

MemTotal: Total usable ram (i.e. physical ram minus a few reserved bits and the kernel binary code)

Could someone update the man page? I'd suggest:

total   Total usable RAM (MemTotal in /proc/meminfo) and total swap space available (SwapTotal in /proc/meminfo)