Reference material is written in a terse, formal style that avoids referring to the reader, and instead focuses on how ~TiddlyWiki itself behaves. The passive voice is often suitable:
Most contracted verb forms are avoided in reference tiddlers. But those ending in <<.word "n't">> (<<.word "aren't">>, <<.word "doesn't">>, <<.word "hasn't">>, <<.word "isn't">>, etc) are acceptable, as they make it less easy to accidentally overlook the word <<.word not>>.