Updated README

Author: ondrejmirtes

Diff for: README.md

@@ -17,6 +17,7 @@
 * Statically declared methods are called statically.
 * Disallow `empty()` - it's a very loose comparison (see [manual](https://secure.php.net/manual/en/function.empty.php)), it's recommended to use more strict one.
 * Always true `instanceof`, type-checking `is_*` functions and strict comparisons `===`/`!==`. These checks can be turned off by setting `checkAlwaysTrueInstanceof`/`checkAlwaysTrueCheckTypeFunctionCall`/`checkAlwaysTrueStrictComparison` to false.
+* Correct case for referenced and called function names.
 
 Additional rules are coming in subsequent releases!