Add unit test for Java code completion in text blocks

[davsclaus]

The Java DSL (In Camel 4.2 onwards) now supports String text-blocks when defining Camel URIs, as shown:

from("""debezium-postgres:customerEvents
        ?databasePassword={{myPassword}}
        &databaseDbname=myDB
        &databaseHostname=myHost
        &pollIntervalMs=2000
        &queryFetchSize=100""")
    .to("kafka:cheese");

[davsclaus]

Okay so this is harder to implement as the endpoint URI completion is based on a single line (or concat strings). A text block is harder for the old logic to handle