doc: make sure section depths are consecutive

skipping heading levels (eg from # to ###, or starting at ###) is legal
in pandoc, but not in nixos-render-docs. pandoc acts as though section
levels *were* consecutive, nixos-render-docs prefers to tell people not
to do that kind of thing because it can make documents more fragile.

1 files changed, 1 insertions, 1 deletions

diff --git a/doc/builders/special/makesetuphook.section.md b/doc/builders/special/makesetuphook.section.md
index fee508dc29c2..eb042412137b 100644
--- a/doc/builders/special/makesetuphook.section.md
+++ b/doc/builders/special/makesetuphook.section.md
@@ -12,7 +12,7 @@ pkgs.makeSetupHook {
 } ./script.sh
 ```
 
-#### setup hook that depends on the hello package and runs hello and @shell@ is substituted with path to bash {#sec-pkgs.makeSetupHook-usage-example}
+### setup hook that depends on the hello package and runs hello and @shell@ is substituted with path to bash {#sec-pkgs.makeSetupHook-usage-example}
 
 ```nix
 pkgs.makeSetupHook {