update elements and fix some bugs

lib/src/prism/tests/languages/sass/atrule-line_feature.test

Index: lib/src/prism/tests/languages/sass/atrule-line_feature.test
diff --git a/lib/src/prism/tests/languages/sass/atrule-line_feature.test b/lib/src/prism/tests/languages/sass/atrule-line_feature.test
new file mode 100644
index 0000000000000000000000000000000000000000..3f2a9669d3d4293586ff5d64ce31751840e1a40f
--- /dev/null
+++ b/lib/src/prism/tests/languages/sass/atrule-line_feature.test
@@ -0,0 +1,35 @@
+@mixin foobar
+@media (min-width: 600px)
+	@include foobar
+
+=foobar
++foobar
+
+----------------------------------------------------
+
+[
+	["atrule-line", [
+		["atrule", "@mixin"],
+		" foobar"
+	]],
+	["atrule-line", [
+		["atrule", "@media"],
+		" (min-width: 600px)"
+	]],
+	["atrule-line", [
+		["atrule", "@include"],
+		" foobar"
+	]],
+	["atrule-line", [
+		["atrule", "="],
+		"foobar"
+	]],
+	["atrule-line", [
+		["atrule", "+"],
+		"foobar"
+	]]
+]
+
+----------------------------------------------------
+
+Checks for at-rules.