docs(doppler): fix download format list and heading levels (#6559)

The download format list included env-no-quotes, which the SecretStore format
CRD enum (json;dotnet-json;env;yaml;docker) does not accept, and omitted docker.
Align the list with the enum so the documented values are actually settable.
Also promote the page title from H2 to H1 and fix use case "6. Download" from
H3 to H2 so all six use cases are at the same level.

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

docs/provider/doppler.md

@@ -1,6 +1,6 @@
 ![Doppler External Secrets Provider](../pictures/doppler-provider-header.jpg)
 
-## Doppler SecretOps Platform
+# Doppler SecretOps Platform
 
 Sync secrets from the [Doppler SecretOps Platform](https://www.doppler.com/) to Kubernetes using the External Secrets Operator.
 
@@ -141,15 +141,15 @@ Then an `ExternalSecret` referencing the `SecretStore`:
 
 ![Doppler name transformer](../pictures/doppler-name-transformer.png)
 
-### 6. Download
+## 6. Download
 
 A single `DOPPLER_SECRETS_FILE` key is set where the value is the secrets downloaded in one of the following formats:
 
 - json
 - dotnet-json
 - env
-- env-no-quotes
 - yaml
+- docker
 
 Downloading secrets requires a specifically configured `SecretStore`: