doc: improve examples.

docs/content/observability/logs.md

@@ -16,12 +16,18 @@ Traefik logs concern everything that happens to Traefik itself (startup, configu
 By default, the logs are written to the standard output.
 You can configure a file path instead using the `filePath` option.
 
-```toml tab="File"
+```toml tab="File (TOML)"
 # Writing Logs to a File
 [log]
   filePath = "/path/to/traefik.log"
 ```
 
+```yaml tab="File (YAML)"
+# Writing Logs to a File
+log:
+  filePath: "/path/to/traefik.log"
+```
+
 ```bash tab="CLI"
 # Writing Logs to a File
 --log.filePath="/path/to/traefik.log"
@@ -31,11 +37,18 @@ You can configure a file path instead using the `filePath` option.
 
 By default, the logs use a text format (`common`), but you can also ask for the `json` format in the `format` option.   
 
-```toml tab="File"
+```toml tab="File (TOML)"
 # Writing Logs to a File, in JSON
 [log]
   filePath = "/path/to/log-file.log"
-  format   = "json"
+  format = "json"
+```
+
+```yaml tab="File (YAML)"
+# Writing Logs to a File, in JSON
+log:
+  filePath: "/path/to/log-file.log"
+  format: json
 ```
 
 ```bash tab="CLI"
@@ -48,11 +61,16 @@ By default, the logs use a text format (`common`), but you can also ask for the
 
 By default, the `level` is set to `ERROR`. Alternative logging levels are `DEBUG`, `PANIC`, `FATAL`, `ERROR`, `WARN`, and `INFO`. 
 
-```toml tab="File"
+```toml tab="File (TOML)"
 [log]
   level = "DEBUG"
 ```
 
+```yaml tab="File (YAML)"
+log:
+  level: DEBUG
+```
+
 ```bash tab="CLI"
 --log.level="DEBUG"
 ```