Correct template-specific workflow syntax (github#5104)

Co-authored-by: Lucas Costi <[email protected]>

content/actions/guides/building-and-testing-nodejs.md

@@ -37,17 +37,17 @@ We recommend that you have a basic understanding of Node.js, YAML, workflow conf
 
 {% data variables.product.prodname_dotcom %} provides a Node.js workflow template that will work for most Node.js projects. This guide includes npm and Yarn examples that you can use to customize the template. For more information, see the [Node.js workflow template](https://github.com/actions/starter-workflows/blob/main/ci/node.js.yml).
 
-To get started quickly, add the template to the `.github/workflows` directory of your repository.
+To get started quickly, add the template to the `.github/workflows` directory of your repository. The workflow shown below assumes that the default branch for your repository is `main`.
 
 {% raw %}
 ```yaml{:copy}
 name: Node.js CI
 
 on:
   push:
-    branches: [ $default-branch ]
+    branches: [ main ]
   pull_request:
-    branches: [ $default-branch ]
+    branches: [ main ]
 
 jobs:
   build:

content/actions/guides/building-and-testing-ruby.md

@@ -31,17 +31,17 @@ We recommend that you have a basic understanding of Ruby, YAML, workflow configu
 
 {% data variables.product.prodname_dotcom %} provides a Ruby workflow template that will work for most Ruby projects. For more information, see the [Ruby workflow template](https://github.com/actions/starter-workflows/blob/master/ci/ruby.yml).
 
-To get started quickly, add the template to the `.github/workflows` directory of your repository.
+To get started quickly, add the template to the `.github/workflows` directory of your repository. The workflow shown below assumes that the default branch for your repository is `main`.
 
 {% raw %}
 ```yaml
 name: Ruby
 
 on:
   push:
-    branches: [ $default-branch ]
+    branches: [ main ]
   pull_request:
-    branches: [ $default-branch ]
+    branches: [ main ]
 
 jobs:
   test:
@@ -105,9 +105,9 @@ name: Ruby CI
 
 on:
   push:
-    branches: [ $default-branch ]
+    branches: [ main ]
   pull_request:
-    branches: [ $default-branch ]
+    branches: [ main ]
 
 jobs:
   test:
@@ -211,9 +211,9 @@ name: Matrix Testing
 
 on:
   push:
-    branches: [ $default-branch ]
+    branches: [ main ]
   pull_request:
-    branches: [ $default-branch ]
+    branches: [ main ]
 
 jobs:
   test:
@@ -272,11 +272,11 @@ name: Ruby Gem
 on:
   # Manually publish
   workflow_dispatch:
-  # Alternatively, publish whenever changes are merged to the default branch.
+  # Alternatively, publish whenever changes are merged to the `main` branch.
   push:
-    branches: [ $default-branch ]
+    branches: [ main ]
   pull_request:
-    branches: [ $default-branch ]
+    branches: [ main ]
 
 jobs:
   build: