[after summer] extractor: should work with multiple modules in inlined configs in Inputs

there are Inputs that have several modules in config header comment.
especially it happens for Filters.

Start by locating the extractor and the inlined config header comments in the test-configs repository, then inspect Inputs for Filters that contain several modules. Done means the extractor handles those multi-module configurations correctly; the issue does not name a specific file or test to run.

Written by the indexing model from the issue text.