Add context info for error to end of first line of message
When adding context info to an error in the content aggregator, append the info the end of the first line of the message rather than the whole message. This makes the message easier to read since subsequent lines of a message are typically trace information.
Here's an example of how the message should appear:
[00:00:00.000] FATAL (antora): antora.yml has invalid syntax; unknown tag !<tag:yaml.org,2002:string> (2:22) in https://example.org/acme-docs.git (ref: main | path: docs)
1 | name: acme
2 | version: !!string 1.0
--------------------------^
3 | title: ACME