[chore][pkg/stanza] Fix example log message (#34016)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
This PR fixes an inconsistency spotted in the docs of the `container`
operator.
Thank's @andrzej-stencel for catching this!

**Link to tracking Issue:** <Issue number if applicable>

**Testing:** <Describe what testing was performed and which tests were
added.>

**Documentation:** <Describe the documentation added.>

Signed-off-by: ChrsMark <[email protected]>

Author: ChrsMark

pkg/stanza/docs/operators/container.md

@@ -76,7 +76,7 @@ Note: in this example the `format: docker` is optional since formats can be auto
 ```json
 {
   "timestamp": "2024-03-30 08:31:20.545192187 +0000 UTC",
-  "body": "log line here",
+  "body": "INFO: log line here",
   "attributes": {
     "time": "2024-03-30T08:31:20.545192187Z", 
     "log.iostream":                "stdout",