fix highlighting of line-height:1.5 in less mode

node_modules/ace/lib/ace/mode/less_highlight_rules.js

@@ -231,7 +231,7 @@ var LessHighlightRules = function() {
                 regex: "\\.[a-z0-9-_]+"
             }, {
                 token: "variable.language",
-                regex: ":[a-z0-9-_]+"
+                regex: ":[a-z_][a-z0-9-_]*"
             }, {
                 token: "constant",
                 regex: "[a-z0-9-_]+"