Renamed the hand "Two Pairs" to "Two Pair".

Nitpick, but the name of the hand is "Two Pair".
https://en.wikipedia.org/wiki/Two_pair#Two_pair

English is a funny language.

This commit does not correct the name of the hand in any images (for
example data/gfx/gui/table/default/handranking.png) because the
corresponding GIMP templates do not have separate text layers, making
them difficult to edit.

src/engine/local_engine/cardsvalue.cpp

@@ -954,7 +954,7 @@ std::string CardsValue::determineHandName(int myCardsValueInt, PlayerList active
 		}
 	}
 	break;
-	// Two Pairs
+	// Two Pair
 	case 2: {
 
 		handName = *cardStringIt_c;
@@ -1775,9 +1775,9 @@ std::list<std::string> CardsValue::translateCardsValueCode(int cardsValueCode)
 		}
 	}
 	break;
-	// Two Pairs
+	// Two Pair
 	case 2: {
-		cardString.push_back("Two Pairs, ");
+		cardString.push_back("Two Pair, ");
 		// erster Pair
 		switch(secondPart) {
 		case 12: