fix some innacuracies in the readme

README.md

@@ -5,6 +5,8 @@ A simple static [Jekyll](https://jekyllrb.com) site for keeping track of recipes
 
 ## Usage
 Ensure that you have [Git](https://git-scm.org), [Ruby](https://www.ruby-lang.org) and [RubyGems](https://rubygems.org/) installed.
+
+Assuming a Unix system:
 ```
 $ git clone https://git.bune.city/lynnesbian/recipe-site
 $ cd recipe-site
@@ -27,6 +29,7 @@ Recipes are found in `_recipes/`, with subrecipes located in `_subrecipes/`.
 
 Here's an example recipe, which could be saved to `_recipes/chocolate_cake.yml`:
 ```yaml
+---
 name: Chocolate cake
 author: Jane Crocker
 layout: recipe
@@ -41,6 +44,7 @@ method:
 - Whisk the egg finely
 # et cetera
 time: 240
+---
 ```
 - `name` (string) - The displayed name of the recipe. Does not appear in the URL.
 - `author` (string, optional) - The author of the recipe.
@@ -49,7 +53,9 @@ time: 240
 - `method` (list) - A list of steps undertaken to create the recipe, written in plain English. Or whatever language you prefer.
 - `time` (string, optional) - The time it takes to make the recipe in minutes.
 
-The recipe's file name isn't important, but it's good practice to make it something obvious, like `chocolate_cake.yml` and not `strawberry_pie.yml`.
+The recipe's file name isn't important, but it's good practice to make it something obvious, like `chocolate_cake.md` and not `strawberry_pie.md`.
+
+The recipe files are standard YAML. The extension should always be `.md` - other extensions will cause issues with subrecipes (see #1).
 
 ### Subrecipes
 Subrecipes behave a little differently to regular recipes:
@@ -59,12 +65,17 @@ Subrecipes behave a little differently to regular recipes:
 
 Subrecipes have a tag that regular recipes do not - the `parents` tag. This is a list of recipes that the subrecipe should be included in. For example:
 ```yaml
+---
 name: Chocolate icing
 parents:
 - chocolate_cake
 - chocolate_cupcakes
+ingredients:
+- [250, chocolate, grams]
+# et cetera
+---
 ```
-The entries in `parents` refer to the filenames of the parent recipes - `chocolate_cake` refers to `chocolate_cake.yml`.
+The entries in `parents` refer to the filenames of the parent recipes - `chocolate_cake` refers to `chocolate_cake.md`.
 
 If a subrecipe does not have at least one valid `parents` entry, it will not appear anywhere on the website.