Add missing const in ModuleLoader

Add the required const to operator == and != as required and warned
about with C++20.

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

source/scriptinterface/ModuleLoader.cpp

@@ -433,12 +433,12 @@ ModuleLoader::Result::iterator& ModuleLoader::Result::iterator::operator++(int)
 	return *this;
 }
 
-[[nodiscard]] bool ModuleLoader::Result::iterator::operator==(const iterator&)
+[[nodiscard]] bool ModuleLoader::Result::iterator::operator==(const iterator&) const
 {
 	return false;
 }
 
-[[nodiscard]] bool ModuleLoader::Result::iterator::operator!=(const iterator&)
+[[nodiscard]] bool ModuleLoader::Result::iterator::operator!=(const iterator&) const
 {
 	return true;
 }