Put test case reference in code block

README.md

@@ -12,7 +12,7 @@ You need will need a C++14 compliant compiler and Lua 5.2 (or higher) installed.
  Linux (g++ 5.1)     | untested | works                     | works
  Everything else     | untested | untested                  | untested
 
-<sup>**1)**</sup> Inherits the integer quirks that come with Lua 5.2, that why the 'types_numeric'
+<sup>**1)**</sup> Inherits the integer quirks that come with Lua 5.2, that why the `types_numeric`
 test case fails.
 
 ## Usage