consistent heading capitalization

Author: ethanpalm

api-playground/asyncapi/setup.mdx

@@ -71,7 +71,7 @@ You can add an `asyncapi` field to any tab or group in the navigation of your `d
   the **api-reference** folder of the docs repo.
 </Note>
 
-## Channel Page
+## Channel page
 
 If you want more control over how you order your channels or if you want to just reference a single channel, you can create an MDX file with the `asyncapi` field in the frontmatter.
 

api-playground/mdx/authentication.mdx

@@ -9,7 +9,7 @@ You can add an authentication method to your `docs.json` to enable it globally o
 
 A page's authentication method will override a global method if both are set.
 
-### Bearer Token
+### Bearer token
 
 <CodeGroup>
 
@@ -32,7 +32,7 @@ authMethod: "bearer"
 
 </CodeGroup>
 
-### Basic Authentication
+### Basic authentication
 
 <CodeGroup>
 
@@ -55,7 +55,7 @@ authMethod: "basic"
 
 </CodeGroup>
 
-### API Key
+### API key
 
 <CodeGroup>
 

api-playground/mdx/configuration.mdx

@@ -81,7 +81,7 @@ You can add an authentication method to your `docs.json` to enable it globally o
 
 A page's authentication method will override a global method if both are set.
 
-### Bearer Token
+### Bearer token
 
 <CodeGroup>
 
@@ -104,7 +104,7 @@ authMethod: "bearer"
 
 </CodeGroup>
 
-### Basic Authentication
+### Basic authentication
 
 <CodeGroup>
 
@@ -127,7 +127,7 @@ authMethod: "basic"
 
 </CodeGroup>
 
-### API Key
+### API key
 
 <CodeGroup>