More config.toml.example cleanups

- Link to more documentation
- Move `changelog-seen` into the "Global Settings" section
- Update incorrect comments on `llvm.link-shared` and
  `rust.debug-assertions`
- Use the correct default in the commented-out example more often
- Clarify that `docs` and `compiler-docs` only control the default,
  they're not a hard-off switch.
- Document `-vvv` and `local-rebuild`
- Minor improvements to doc-comments in config.toml.example

This also sets `download-rustc = false`; that was already the default,
but it will be helpful in case the default changes
(https://jyn.dev/2023/01/12/Bootstrapping-Rust-in-2023.html).

1 files changed, 3 insertions, 1 deletions

diff --git a/src/bootstrap/defaults/config.user.toml b/src/bootstrap/defaults/config.user.toml
index ee271c3fb51..25d9e649f23 100644
--- a/src/bootstrap/defaults/config.user.toml
+++ b/src/bootstrap/defaults/config.user.toml
@@ -8,9 +8,11 @@ doc-stage = 2
 # When compiling from source, you usually want all tools.
 extended = true
 
+# Most users installing from source want to build all parts of the project from source.
 [llvm]
-# Most users installing from source want to build all parts of the project from source, not just rustc itself.
 download-ci-llvm = false
+[rust]
+download-rustc = false
 
 [dist]
 # Use better compression when preparing tarballs.