For each command in the list of builtins create a file in man/man1 called:

${command}.1

eg.
for.1
type.1
alias.1
etc.

All these files are identical as follows:

jaws@jaws(264)$ cat alias.1
.so man1/bash_builtins.1
jaws@jaws(265)$ 

Make sure you adjust the .so line in bash_builtins.1 to reflect where you
put it.