docs: fix note blocks

docs/manual/nix-flakes/standalone.md

@@ -48,7 +48,7 @@ $ # And after the initial activation.
 $ home-manager switch --flake ~/hmconf
 ```
 
-::: note
+::: {.note}
 The flake inputs are not automatically updated by Home Manager. You need
 to use the standard `nix flake update` command for that.
 

docs/manual/usage.md

@@ -5,7 +5,7 @@ which is typically found at `~/.config/home-manager/home.nix` in the
 standard installation or `~/.config/home-manager/flake.nix` in a Nix
 flake based installation.
 
-::: note
+::: {.note}
 The default configuration used to be placed in `~/.config/nixpkgs`¸ so
 you may see references to that elsewhere. The old directory still works
 but Home Manager will print a warning message when used.

docs/manual/usage/configuration.md

@@ -29,7 +29,7 @@ A fresh install of Home Manager will generate a minimal
 
 You can use this as a base for your further configurations.
 
-::: note
+::: {.note}
 If you are not very familiar with the Nix language and NixOS modules
 then it is encouraged to start with small and simple changes. As you
 learn you can gradually grow the configuration with confidence.