Use two hashes in snippet.

docs/markdown/snippets/gnome-rsp-files-support.md

diff --git a/docs/markdown/snippets/gnome-rsp-files-support.md b/docs/markdown/snippets/gnome-rsp-files-support.md
index 0506cf7..29c9082 100644
--- a/docs/markdown/snippets/gnome-rsp-files-support.md
+++ b/docs/markdown/snippets/gnome-rsp-files-support.md
@@ -1,4 +1,4 @@
-# Support response files for custom targets
+## Support response files for custom targets
 
 When using the Ninja backend, Meson can now pass arguments to supported tools
 through response files.