(ITS#8769) Docs: Fix oid search extension syntax

[lukas.juhrich@agdsn.de]

Full_Name: Lukas Juhrich
Version: 2.4.45
OS: Arch Linux, Debian Stretch
URL: http://agdsn.me/~lukasjuhrich/openldap/
Submission from: (NULL) (141.76.119.134)


This is a small syntax fix to adapt the documentation to how the code actually
parses `-E <oid>` options.

Quicklink to the code responsible for parsing:
http://www.openldap.org/devel/gitweb.cgi?p=openldap.git;a=blob;f=clients/tools/ldapsearch.c;h=f05cd06d0c801ae296e1346f84314a8e41378900;hb=HEAD#l648

I was not sure whether patches should also follow the naming convention, so I
provided the same patch using two different names, the original one and the one
adhering to the naming convention.