quoting of enumerations is okay, so let this be okay to carto tests

test/errorhandling/invalid_value.mss

@@ -1,5 +1,4 @@
 #world[zoom=5] {
   text-face-name: 2;
-  line-rasterizer: 'full';
   text-name: 'foo';
 }

test/errorhandling/invalid_value.result

@@ -1,2 +1 @@
 invalid_value.mss:2:2 Invalid value for text-face-name, the type font is expected. 2 (of type float)  was given.
-invalid_value.mss:3:2 Invalid value for line-rasterizer, the type keyword (options: full, fast) is expected. full (of type string)  was given.

test/rendering-mss/variable-quoting-of-enum.mss

@@ -0,0 +1,5 @@
+#world {
+  line-rasterizer: 'fast';
+  // carto should collapse to one
+  line-rasterizer: fast;
+}

test/rendering-mss/variable-quoting-of-enum.xml

@@ -0,0 +1,5 @@
+<Style name="style" filter-mode="first">
+  <Rule>
+    <LineSymbolizer rasterizer="fast" />
+  </Rule>
+</Style>