"Unrecognized field hyperlink-source" despite being in the default config

**Describe the bug**
the default cabal-install config mentions an option under `haddock` called `hyperlink-source`, but if I uncomment it then it gives `Unrecognized field hyperlink-source`

**To Reproduce**
- [re]move any existing `~/.cabal/config` file
- run `cabal user-config init`
- uncomment the line ` -- hyperlink-source: False` in the generated config
- run `cabal user-config diff`

**Expected behavior**
the default config shouldn't include options that aren't recognized

**System information**
- arch linux, kernel version 6.17.9-arch1-1
- cabal-install 3.16.0.0 and ghc 9.12.2, both fetched using ghcup 0.1.50.2

**Additional context**
i was playing with the options because i noticed that libraries i get from hackage didn't have their source code pages generated when i used `cabal haddock-project`