DERBY-4691.diff, DERBY-4691.stat, and DERBY-4691.zip, with changes to 9 of the system table files.
Okay, I sort of went crazy.
Wherever there was a reference to an org.apache.derby API class, I fixed the formatting for it and also did the following:
Lowercased nullability value, uppercased descriptions
Put in empty columns
Removed periods at end of descriptions unless multiple sentences are used
For needed line breaks in columns, used a line break, not a space, where a space didn't work in the one-page HTML (the PDF is another problem that may be insoluble)
Added shortdesc element and index entries where these were missing
Clarified a sentence at the end of the SYSTRIGGERS topic that made no sense to me because I thought it was referring to the SYSSTATEMENTS.ACTIONID column. (A space between the period and the column name occurs often enough that this was deceptive.)
Corrected the description of the SYSSTATISTICS table (it was copied from SYSSCHEMAS, apparently).
We're still not fully consistent because I touched only 9 of about 21 topics.
Let me know if there's anything odd about any of the attachments. I'm running from home using Windows instead of my usual Unix system.