Rudder

Current split is not good, and we can't fix it without preventing easy upmerging.

We will:

• concatenante all .adoc sources in the right order
• Split page title level like webhelp does
• Reset title level in each page to match antora practice
• Generate files by title hierarchy, using titles slugs
• Generate redirect map for old doc (without hierarchy) to the new one
• Try to allow redirecting the other way (to old docs)

Then use the result as build source for reference manual.