Fix Nif doc typos
Merge branch 'hirotnk/nif-typo-fix' into maint

* hirotnk/nif-typo-fix:
  Fix Nif doc typos
Fix data type overflow in the OTP-MIB erlNodeReductions field.

This patch fixes an error when querying the erlNodeReductions
field via SNMP on nodes with high uptime. The previous
definition of the OTP-MIB only allowed 32bit values to be
returned. This was now changed to be able to return 64bit
values.