Fix table accessibility issues (#56450)

Author: heiskr

content/code-security/secret-scanning/introduction/supported-secret-scanning-patterns.md

@@ -55,6 +55,7 @@ This table lists the secrets supported by {% data variables.product.prodname_sec
 In addition to these generic non-provider patterns, {% data variables.product.prodname_secret_scanning %} uses {% data variables.product.prodname_copilot_short %} to detect generic passwords. For more information, see [AUTOTITLE](/code-security/secret-scanning/copilot-secret-scanning/responsible-ai-generic-secrets).
 {% endif %}
 
+{caption="Non-provider secret scanning patterns"}
 | Provider | Token |
 |----------|:--------------------|
 |  Generic | http_basic_authentication_header |

content/copilot/concepts/copilot-billing/understanding-and-managing-requests-in-copilot.md

@@ -86,6 +86,8 @@ Each model has a premium request multiplier, based on its complexity and resourc
 
 If you use **{% data variables.copilot.copilot_free_short %}**, you have access to a limited number of models, and each model will consume one premium request when used. For example, if you make a request using the {% data variables.copilot.copilot_o3_mini %} model, your interaction will consume **one premium request**, not 0.33 premium requests.
 
+{% rowheaders %}
+
 | Model                                                                   | Multiplier for **paid plans**  | Multiplier for **{% data variables.copilot.copilot_free_short %}** |
 |-------------------------------------------------------------------------|--------------------------------|-----------------------|
 | {% data variables.copilot.copilot_gpt_41 %}                             | 0                              | 1                     |
@@ -103,6 +105,8 @@ If you use **{% data variables.copilot.copilot_free_short %}**, you have access
 | {% data variables.copilot.copilot_o3_mini %}                            | 0.33                           | 1                     |
 | {% data variables.copilot.copilot_o4_mini %}                            | 0.33                           | Not applicable        |
 
+{% endrowheaders %}
+
 ## Examples of premium request usage
 
 Premium request usage is based on the model’s multiplier and the feature you’re using. For example:

data/reusables/actions/supported-shells.md

@@ -1,3 +1,4 @@
+{caption="Supported platforms and shell parameters for GitHub Actions"}
 | Supported platform | `shell` parameter | Description                                                                                                                                                                                                                                                                             | Command run internally                          |
 | ------------------ | ----------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------- |
 | Linux / macOS      | unspecified       | The default shell on non-Windows platforms. Note that this runs a different command to when `bash` is specified explicitly. If `bash` is not found in the path, this is treated as `sh`.                                                                                                | `bash -e {0}`                                   |