docs: Add language to code blocks.

docs/production/authentication-methods.md

@@ -330,7 +330,7 @@ settings in `/etc/zulip/settings.py`.
 
 An example configation for Active Directory group restriction can be:
 
-```
+```python
 import django_auth_ldap
 AUTH_LDAP_GROUP_TYPE = django_auth_ldap.config.ActiveDirectoryGroupType()
 
@@ -613,7 +613,7 @@ integration](../production/scim.md).
 
    Save the certificate in a new `{idp_name}.crt` file constructed as follows:
 
-   ```
+   ```text
    -----BEGIN CERTIFICATE-----
    {Paste the content here}
    -----END CERTIFICATE-----
@@ -676,7 +676,7 @@ this with another IdP.
    `/etc/zulip/settings.py` as `slo_url`. For example it may look like
    this:
 
-   ```
+   ```text
    "your_keycloak_idp_name": {
        "entity_id": "https://keycloak.example.com/auth/realms/yourrealm",
        "url": "https://keycloak.example.com/auth/realms/yourrealm/protocol/saml",

docs/production/deployment.md

@@ -511,7 +511,7 @@ Apache requires you use the hostname, not the IP address; see
 
 1. Enable some required Apache modules:
 
-   ```
+   ```bash
    a2enmod ssl proxy proxy_http headers rewrite
    ```
 

docs/production/email-gateway.md

@@ -122,7 +122,7 @@ Congratulations! The integration should be fully operational.
 1. Test your configuration by sending emails to the target email
    account and then running the Zulip tool to poll that inbox:
 
-   ```
+   ```bash
    su zulip -c '/home/zulip/deployments/current/manage.py email_mirror'
    ```
 

docs/production/scim.md

@@ -23,13 +23,13 @@ The Zulip server-side configuration is straightforward:
    example, if your organization is hosted on a subdomain
    (`subdomain.zulip.example.com`):
 
-   ```
+   ```bash
    /home/zulip/deployments/current/manage.py add_scim_client okta -r 'subdomain'
    ```
 
    Or your organization is hosted on the root domain (`zulip.example.com`):
 
-   ```
+   ```bash
    /home/zulip/deployments/current/manage.py add_scim_client okta -r ""
    ```
 
@@ -39,7 +39,7 @@ The Zulip server-side configuration is straightforward:
 1. Configure the Zulip server by adding a `SCIM_CONFIG` block to your
    `/etc/zulip/settings.py`:
 
-   ```
+   ```python
    SCIM_CONFIG = {
        "subdomain": {
            "bearer_token": "<secret token>",