* Add detectable key to languages
This key allows to override the language being included in the
language stats of a repository.
* Make detectable override-able using .gitattributes
* Mention `linguist-detectable` in README
* Remove detectable key from languages
Reverts changes in 0f7c0df5.
* Update commit hash to the one that was merged
PR #3806 changed the commit hash. The original commit was not
actually merged into the test/attributes branch.
* Fix check to ensure detectable is defined
* Add include in language stats tests when detectable set
* Ignore detectable when vendored, documentation or overridden
* Add documentation on detectable override in README
* Improve documentation on detectable override in README
Documentation is an important part of a software project but is not
generally thought of as part of the code for that project. Repository
language statistics are used to quantify the project's code, so it makes
sense to exclude documentation from those computations.
Documentation files are recognized similarly to vendored files.
lib/linguist/documentation.yml contains regular expressions to match
common names for documentation files. A new linguist-documentation Git
attribute can be used to override those conventions.
This gives us a consistent test framework across all Ruby versions which
should help avoid errors that are only found when CI runs the tests on
different Rubies. (And this fixes an immediate bug where there's no
`skip` method in the version of test-unit we're currently using only on
Ruby 2.2.)
