I agree that the information should be in the manpage -- in many distributions of the manpage it is, but not mine, either.
Code:
/ is a directory
@ is a symlink
| is a named pipe (fifo)
= is a socket.
* for executable files
> is for a "door" -- a file type currently not implemented for Linux, but supported on Sun/Solaris.
Files not matching any of the above description are regular files and so get no indicator.