Add a supplementary explanation to function `get_syscall_fnname` (#2593)
Add a supplementary explanation to function `get_syscall_fnname` (#2593)

* add a supplementary explanation to function `get_syscall_fnname`.
* fix the contents

tuxology/bcc,tuxology/bcc,iovisor/bcc,brendangregg/bcc,brendangregg/bcc,iovisor/bcc,iovisor/bcc,tuxology/bcc,tuxology/bcc,brendangregg/bcc,tuxology/bcc,iovisor/bcc,iovisor/bcc,brendangregg/bcc,brendangregg/bcc