Mark .indent.pro files as vendored (#3361)

lib/linguist/vendor.yml

@@ -50,6 +50,9 @@
 # Go dependencies
 - Godeps/_workspace/
 
+# GNU indent profiles
+- .indent.pro
+
 # Minified JavaScript and CSS
 - (\.|-)min\.(js|css)$
 

test/test_file_blob.rb

@@ -294,6 +294,8 @@ class TestFileBlob < Minitest::Test
     assert !sample_blob("Godeps/Godeps.json").vendored?
     assert sample_blob("Godeps/_workspace/src/github.com/kr/s3/sign.go").vendored?
 
+    assert sample_blob(".indent.pro").vendored?
+
     # Rails vendor/
     assert sample_blob("vendor/plugins/will_paginate/lib/will_paginate.rb").vendored?