In 3.6 Milestone 2 spelling check will also be available on help editor source pages (bug 286203). By help editors I mean Context Help editor, Table of Contents editor and Cheat Sheet editor. These editors has a source page which reveals the actual XML contents of the files. The page will now check spelling for all the quoted strings (Text enclosed with single or double quotes). The XML comments, tags and attributes will be excluded from spell checking.
Cheat Sheet Editor - Source Page
The spelling errors are marked with usual annotations that you would find in any other place such as properties file. Quick fix will be available for these annotations, suggesting the possible correct spellings.
Quick fixing spelling errors
Customizing spelling check preferences
The spell check options can be controlled from the Spelling Preference page. See Windows -> Preferences -> General -> Editors -> Text Editors -> Spelling.
This page controls the dictionary and spell checking rules.Spelling Preferences page
Few more enhancements are already planned specific to the XML format of these help files. See bug 289926. Feel free to add anything to it that you feel will make life easier.