docs(scaleway): mark referent auth in matrix and fix headings (#6581)

The support matrix left referent authentication blank for Scaleway, but the
provider supports it: the credential secretRef is validated with the relaxed
ValidateReferentSecretSelector and resolved via resolvers.SecretKeyRef against the
ExternalSecret namespace. Set it x. Also promote the page headings (H2 title to H1,
H3 sections to H2).

Signed-off-by: Alexander Chernov <alexander@chernov.it>

docs/introduction/stability-support.md

@@ -125,7 +125,7 @@ The following table show the support for features across different providers.
 | senhasegura DSM           |              |              |                      |            x            |        x         |             |              x              |
 | Doppler                   |      x       |              |                      |                         |        x         |             |                             |
 | Keeper Security           |      x       |              |                      |                         |        x         |      x      |                             |
-| Scaleway                  |      x       |      x       |                      |                         |        x         |      x      |              x              |
+| Scaleway                  |      x       |      x       |                      |            x            |        x         |      x      |              x              |
 | CyberArk Secrets Manager  |      x       |      x       |                      |                         |        x         |             |                             |
 | Delinea                   |      x       |              |                      |                         |        x         |             |                             |
 | Beyondtrust               |              |              |                      |                         |        x         |      x      |                             |

docs/provider/scaleway.md

@@ -1,8 +1,8 @@
-## Scaleway Secret Manager
+# Scaleway Secret Manager
 
 External Secrets Operator integrates with [Scaleway's Secret Manager](https://developers.scaleway.com/en/products/secret_manager/api/v1alpha1/).
 
-### Creating a SecretStore
+## Creating a SecretStore
 
 You need an api key (access key + secret key) to authenticate with the secret manager.
 Both access and secret keys can be specified either directly in the config, or by referencing
@@ -26,7 +26,7 @@ spec:
           key: <KEY_IN_KUBE_SECRET>
 ```
 
-### Referencing Secrets
+## Referencing Secrets
 
 Secrets can be referenced by name, id or path, using the prefixes `"name:"`, `"id:"` and `"path:"` respectively.
 
@@ -49,7 +49,7 @@ spec:
           version: latest_enabled
 ```
 
-### JSON Secret Values
+## JSON Secret Values
 
 Scaleway Secret Manager supports storing JSON objects as secrets. You can access values using [gjson syntax](https://github.com/tidwall/gjson/blob/master/SYNTAX.md):