[slides][props] minor cleanup

slides/properties.md

@@ -178,11 +178,11 @@ namespace Dumux::Properties {
 namespace TTag { struct MyTypeTag {}; }
 
 // some property tag
-template<typename TypeTag> struct SomeTag;
+template<typename TypeTag> struct PropTagA;
 
 // property definition for MyTypeTag
 template<>
-struct SomeTag<MyTypeTag>
+struct PropTagA<MyTypeTag>
 { using type = /*the actual property*/; };
 }  // namespace Dumux::Properties
 ```
@@ -196,8 +196,8 @@ A simplified example to illustrate the idea
 template<class TypeTag>
 class GenericClass
 {
-    using PropA = typename Properties::Tag<TypeTag>::type;
-    using PropB = typename Properties::OtherTag<TypeTag>::type;
+    using PropA = typename Properties::PropTagA<TypeTag>::type;
+    using PropB = typename Properties::PropTagB<TypeTag>::type;
     // ...
     // A property could be, for instance, a fluid system
     using FS = typename Properties::FluidSystem<TypeTag>::type;