This is supposed to firstly improve the docs as they are, and secondly hint at how the core conceptual information ought to be moved to the store derivation section of the manual. Co-authored-by: Jörg Thalheim <Mic92@users.noreply.github.com>
Note, this includes some text adapted from from Eelco's dissertation
doc/manual{src -> source}
This is needed to avoid this https://github.com/mesonbuild/meson/issues/13774 when we go back to making our subproject directory `src`.