Update README.developer

fix typo

Author: brianjester

README.developer

@@ -331,7 +331,7 @@ Additionally, you may want to add the '--with-perl-binding' or
 '--with-python-binding' or '--with-tcl-binding' or '--with-lua-binding' if you are
 interested in SWIG binding support for those scripting languages.
 
-For LUA bindinds if you run "lua luatest.lua" and see this error message:
+For LUA bindings if you run "lua luatest.lua" and see this error message:
 luatest.lua:44: Error in Rig::set_mode (arg 2), expected 'rmode_t' got 'string'
 This means you need to upgrade both swig and lua for 64-bit lua support
 This is known to work on swig 4.0.1 and lua 5.3.5