docs: improve facade

facade/src/test/java/com/iluwatar/facade/DwarvenGoldmineFacadeTest.java

@@ -84,7 +84,7 @@ class DwarvenGoldmineFacadeTest {
     // Now do some actual work, start digging gold!
     goldMine.digOutGold();
 
-    // Since we gave the dig command, every worker should be doing it's job ...
+    // Since we gave the dig command, every worker should be doing its job ...
     assertTrue(appender.logContains("Dwarf gold digger digs for gold."));
     assertTrue(appender.logContains("Dwarf cart operator moves gold chunks out of the mine."));
     assertTrue(appender.logContains("Dwarven tunnel digger creates another promising tunnel."));