[logger] Flatten messageText when no file is provided in the diagnostic output. (#802)
[logger] Flatten messageText when no file is provided in the diagnostic output. (#802)

Fixes #495
sebastian-lenz/typedoc,PolymerLabs/typedoc,TypeStrong/typedoc,TypeStrong/typedoc,PolymerLabs/typedoc,PolymerLabs/typedoc,sebastian-lenz/typedoc,TypeStrong/typedoc,sebastian-lenz/typedoc