Update style-guide advice about functions (#826)

modules/ROOT/pages/styleguide.adoc

@@ -14,8 +14,8 @@ For rules and recommendations for naming of labels, relationship types and prope
 
 * When using Cypher language constructs in prose, use a `monospaced` font and follow the styling rules.
 * When referring to labels and relationship types, the colon should be included as follows: `:Label`, `:REL_TYPE`.
-* When referring to functions, use lower camel case and parentheses should be used as follows: `shortestPath()`.
-Arguments should normally not be included.
+* When referring to functions, use lower camel case and parentheses.
+For example: `toString()`.
 * If you are storing Cypher statements in a separate file, use the file extension `.cypher`.