Sections 2 and 3 have RETURN VALUES, not DIAGNOSTICS

jemalloc.3: fix malformed CVS Id

Add malloc.conf to the NAME section
Remove Pp before Bd at few places

Use Mt for email addresses.

branches: 1.8.2; 1.8.8; 1.8.12;
Sort sections.

Note the potential danger in the options. Fixes PR lib/31112.

Fix prologue macros order.

branches: 1.5.4;
Use standard section headers.

Join %U.

Fix previous commit by also moving the type of _malloc_options. In addition,
add a (commented) note that _malloc_message should be documented better.

Move the '_malloc_options' variable from malloc(3) to jemalloc(3).

Split the implementation details of malloc(3) to a separate jemalloc(3)
manual page. This way malloc(3) can follow the standard terse format used
elsewhere in the libc, while additional details can be added to jemalloc(3).

Note HISTORY and AUTHORS in jemalloc(3), and add some reading material to
SEE ALSO.