Fix .devcontainer.json language (take two) (github#15813)

Fix .devcontainer.json language (take two)

content/github/developing-online-with-codespaces/configuring-codespaces-for-your-project.md

@@ -21,7 +21,9 @@ If you don't define a configuration in your repository, {% data variables.produc
 
 You can create a default codespace configuration using a pre-built container configuration for your project type, or you can create a custom configuration specific to your project's needs.
 
-{% data variables.product.prodname_codespaces %} uses settings contained in a file named `devcontainer.json` in the root of the repository or in a `.devcontainer` folder. You can use `devcontainer.json` to set default settings for the entire codespace environment, including the {% data variables.product.prodname_vscode %} editor, but you can also set editor-specific settings in a file named `.vscode/settings.json`.
+{% data variables.product.prodname_codespaces %}  uses settings contained in a configuration file named `devcontainer.json`. {% data reusables.codespaces.devcontainer-location %}
+
+You can use your `devcontainer.json` to set default settings for the entire codespace environment, including the {% data variables.product.prodname_vscode %} editor, but you can also set editor-specific settings in a file named `.vscode/settings.json`.
 
 Changes to a repository's codespace configuration apply only to every new codespace and do not affect any existing codespace.
 
@@ -38,7 +40,9 @@ Each new codespace created from a branch which contains the `.devcontainer` fold
 
 ### Creating a custom codespace configuration
 
-If none of the pre-built configurations meet your needs, you can create a custom configuration by adding a `devcontainer.json` file to the root of your repository or a `.devcontainer` folder. In the file, you can use supported configuration keys to specify aspects of the codespace's environment, like which {% data variables.product.prodname_vscode %} extensions will be installed.
+If none of the pre-built configurations meet your needs, you can create a custom configuration by adding a `devcontainer.json` file. {% data reusables.codespaces.devcontainer-location %}
+
+In the file, you can use supported configuration keys to specify aspects of the codespace's environment, like which {% data variables.product.prodname_vscode %} extensions will be installed.
 
 {% data reusables.codespaces.vscode-settings-order %}
 

data/reusables/codespaces/devcontainer-location.md

@@ -0,0 +1 @@
+This file can be located in the root of the repository or in a folder called `.devcontainer`. If the file is located in the root of the repository, the filename must begin with a period: `.devcontainer.json`.