Fix TrailingSemicolon linter for @includes with blocks

This fixes sds#198

A recent commit [1] generalized the TrailingSemicolon linter to also
check `@extend` and `@include`. This commit did not take into account
`@include`s with a block. @Steffen185 provided a simple repro case:

  $ cat test.scss
  body {
    @include foo {
      background: #f00;
    }
  }
  $ scss-lint test.scss
  test.scss:2 [W] TrailingSemicolon: Declaration should not have a space
  before the terminating semicolon

I took this case and added it to the spec for the TrailingSemicolon
linter. The fix included checking the `@include` for children, and in
such case continue checking children. There was already code for this
scenario for props, so I just refactored a bit to make use of the same
solution.

[1]: sds@58689b1d18c7449509168f

Change-Id: If8f178d7b36a048bb7c00e75b0738b9efe0530ed
Reviewed-on: http://gerrit.causes.com/40988
Tested-by: jenkins <[email protected]>
Reviewed-by: Shane da Silva <[email protected]>

lib/scss_lint/linter/trailing_semicolon.rb

@@ -3,26 +3,25 @@ module SCSSLint
   class Linter::TrailingSemicolon < Linter
     include LinterRegistry
 
-    def visit_prop(node)
-      if has_nested_properties?(node)
-        yield # Continue checking children
-      else
-        check_semicolon(node)
-      end
-    end
-
     def visit_extend(node)
       check_semicolon(node)
     end
 
-    def visit_mixin(node)
+    def visit_variable(node)
       check_semicolon(node)
     end
 
-    def visit_variable(node)
-      check_semicolon(node)
+    def visit_possible_parent(node)
+      if has_nested_properties?(node)
+        yield # Continue checking children
+      else
+        check_semicolon(node)
+      end
     end
 
+    alias_method :visit_mixin, :visit_possible_parent
+    alias_method :visit_prop,  :visit_possible_parent
+
   private
 
     def has_nested_properties?(node)

spec/scss_lint/linter/trailing_semicolon_spec.rb

@@ -156,6 +156,18 @@
     it { should report_lint line: 2 }
   end
 
+  context 'when @include takes a block' do
+    let(:css) { <<-CSS }
+      .foo {
+        @include bar {
+          border: 0;
+        }
+      }
+    CSS
+
+    it { should_not report_lint }
+  end
+
   context 'when @extend ends with a semicolon' do
     let(:css) { <<-CSS }
       .foo {