Add support for dashes in filenames to test context extractor

[bidds95]

It looks like commit #b75b523 may have inadvertently broken support for dashes in filenames. A small change to the regex pattern in _extract_includes() fixes the issue.

I haven't found any open issues or anything to suggest support was dropped (Issue #439 suggests it was supported in release 1.0.0). Let me know if I've missed something.

I've tweaked an existing unit test to cover dashes in filenames.

[swaldhoer]

Isn't this already fixed in https://github.com/ThrowTheSwitch/Ceedling/commit/d3c0bffd8a2daef028c9803ccd6e7e107fc97f15 (issue https://github.com/ThrowTheSwitch/Ceedling/issues/780)?

[bidds95]

Isn't this already fixed in d3c0bff (issue #780)?

Hi @swaldhoer, I think these might be different issues. This issue affects the include directive whereas issue #780 only affects test filenames. For example, I spotted this when a mock wasn't being generated for a file which included dashes in the name, but I think it affects more than just mock generation.

[swaldhoer]

Ah sorry yes I think you are correct