Pass to address spelling issues.
Most of these are just in comments or user-facing messages, but there were a couple that could impact script behavior. E.g. Server/test/test_SDP.py and Unsupported/Maintenance/sdputils.py looking at files or paths that don't exist.
1. I did not do anything with PDF files as I assume those are automatically generated.
2. This pass did address SDP-637, although I did it in the .adoc and .html files instead of the PDF.
3. I eventually realized Robert may have written some of these but I'd already saved the files changing things like "customisation" -> "customization" or "behaviour" -> "behavior". Sorry :(