docs(senhasegura): mark deletion + referent in matrix and fix title (#6583)

The support matrix left DeletionPolicy and referent authentication blank for
senhasegura DSM, but both work: GetSecret returns NoSecretErr on a missing secret
(read-side deletionPolicy fires), and the auth secretRef resolves via
resolvers.SecretKeyRef with no strict validator (namespace-less ClusterSecretStore
ref resolves against the ExternalSecret namespace). Set both x. Also promote the
page title from H2 to H1.

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

docs/introduction/stability-support.md

@@ -122,7 +122,7 @@ The following table show the support for features across different providers.
 | 1Password                 |      x       |      x       |                      |                         |        x         |      x      |              x              |
 | 1Password SDK             |              |              |                      |                         |        x         |      x      |              x              |
 | Generic Webhook           |              |              |                      |                         |                  |             |              x              |
-| senhasegura DSM           |              |              |                      |                         |        x         |             |                             |
+| senhasegura DSM           |              |              |                      |            x            |        x         |             |              x              |
 | Doppler                   |      x       |              |                      |                         |        x         |             |                             |
 | Keeper Security           |      x       |              |                      |                         |        x         |      x      |                             |
 | Scaleway                  |      x       |      x       |                      |                         |        x         |      x      |              x              |

docs/provider/senhasegura-dsm.md

@@ -1,4 +1,4 @@
-## Segura® DevOps Secret Manager (DSM)
+# Segura® DevOps Secret Manager (DSM)
 
 External Secrets Operator integrates with [Segura®](https://segura.security/) [DevOps Secret Manager (DSM)](https://segura.security/solutions/devops) module to sync application secrets to secrets held on the Kubernetes cluster.