docs: Adds coder_git_auth deprication notice (#203)

Author: kyle-pazdel

docs/data-sources/external_auth.md

@@ -3,16 +3,15 @@
 page_title: "coder_external_auth Data Source - terraform-provider-coder"
 subcategory: ""
 description: |-
-  Use this data source to require users to authenticate with an external service prior to workspace creation. This can be used to pre-authenticate external services in a workspace. (e.g. gcloud, gh, docker, etc)
+  Use this data source to require users to authenticate with an external service prior to workspace creation. This can be used to pre-authenticate external services in a workspace. (e.g. gcloud, GitHub, docker, etc)
 ---
 
 # coder_external_auth (Data Source)
 
-Use this data source to require users to authenticate with an external service prior to workspace creation. This can be used to pre-authenticate external services in a workspace. (e.g. gcloud, gh, docker, etc)
-
-
+Use this data source to require users to authenticate with an external service prior to workspace creation. This can be used to pre-authenticate external services in a workspace. (e.g. gcloud, GitHub, docker, etc)
 
 <!-- schema generated by tfplugindocs -->
+
 ## Schema
 
 ### Required

docs/data-sources/git_auth.md

@@ -8,7 +8,7 @@ description: |-
 
 # coder_git_auth (Data Source)
 
-Use this data source to require users to authenticate with a Git provider prior to workspace creation. This can be used to perform an authenticated `git clone` in startup scripts.
+⚠️ **Deprecation Notice:** This data source is deprecated and will be removed in a future release. Please use the `coder_external_auth` data source ([here](https://github.com/coder/terraform-provider-coder/blob/main/docs/data-sources/external_auth.md)) instead.
 
 ## Example Usage
 
@@ -37,6 +37,7 @@ EOF
 ```
 
 <!-- schema generated by tfplugindocs -->
+
 ## Schema
 
 ### Required