docs: fix core_pipe_limit info

core_pipe_limit:

This sysctl is only applicable when core_pattern is configured to pipe core

files to user space helper a (when the first character of core_pattern is a '|',

files to a user space helper (when the first character of core_pattern is a '|',

see above).  When collecting cores via a pipe to an application, it is

occasionally usefull for the collecting application to gather data about the

occasionally useful for the collecting application to gather data about the

crashing process from its /proc/pid directory.  In order to do this safely, the

kernel must wait for the collecting process to exit, so as not to remove the

crashing processes proc files prematurely.  This in turn creates the possibility

processes above that value are noted via the kernel log and their cores are

skipped.  0 is a special value, indicating that unlimited processes may be

captured in parallel, but that no waiting will take place (i.e. the collecting

process is not guaranteed access to /proc/<crahing pid>/).  This value defaults

process is not guaranteed access to /proc/<crashing pid>/).  This value defaults

to 0.

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