Improve query expression documentation

[amotl]

Introduction

This is about writing query expressions properly.

Searching for names

uspto-peds search 'appExamName:"WILSON, NICHOLAS R"'

Note the quotes around the examiner name here.

-- #10 (comment)

Searching for (multiple) document numbers

1. For querying numberlists, propose an expression like (see also Result returns too many docs #10 (comment))

uspto-peds search 'patentNumber:(6583088 OR 6875727 OR 8697602)'

2. Improve querying numberlists by providing an appropriate --numberlist= command line option.