Preserve newlines when converting @CsvSource(textBlock = ...) to @ValueSource

[timtebeek]

Summary

When CsvSourceToValueSource converts a multi-line @CsvSource(textBlock = """...""") to @ValueSource, each value is now placed on its own indented line instead of being collapsed onto a single line. Previously the textBlock branch produced output like @ValueSource(strings = {"a", "b", "c"}); it now produces a block-style array aligned with the annotation. Internal cleanup along the way: the five per-type format* helpers collapse into one Function<String,String> mapper pipeline using Collectors.joining, and the custom indent helper is replaced with Space.getIndent().

Test plan

• Updated existing replaceTextBlockAttribute* test expectations to match the new layout
• Added replaceTextBlockAttributePlacesEachItemOnItsOwnLine regression test mirroring the FindLocaleDateTimeFormatsTest case from the issue
• Full ./gradlew test passes