RBMap: Add explicit copy operators to iterators

Absence thereof is deprecated and breaks builds on most compilers.

Bonus: Fix parameter naming style throughout.

core/templates/rb_map.h

@@ -111,11 +111,16 @@ public:
 			return *this;
 		}
 
-		_FORCE_INLINE_ bool operator==(const Iterator &b) const { return E == b.E; }
-		_FORCE_INLINE_ bool operator!=(const Iterator &b) const { return E != b.E; }
+		_FORCE_INLINE_ bool operator==(const Iterator &p_it) const { return E == p_it.E; }
+		_FORCE_INLINE_ bool operator!=(const Iterator &p_it) const { return E != p_it.E; }
 		explicit operator bool() const {
 			return E != nullptr;
 		}
+
+		Iterator &operator=(const Iterator &p_it) {
+			E = p_it.E;
+			return *this;
+		}
 		Iterator(Element *p_E) { E = p_E; }
 		Iterator() {}
 		Iterator(const Iterator &p_it) { E = p_it.E; }
@@ -138,11 +143,16 @@ public:
 			return *this;
 		}
 
-		_FORCE_INLINE_ bool operator==(const ConstIterator &b) const { return E == b.E; }
-		_FORCE_INLINE_ bool operator!=(const ConstIterator &b) const { return E != b.E; }
+		_FORCE_INLINE_ bool operator==(const ConstIterator &p_it) const { return E == p_it.E; }
+		_FORCE_INLINE_ bool operator!=(const ConstIterator &p_it) const { return E != p_it.E; }
 		explicit operator bool() const {
 			return E != nullptr;
 		}
+
+		ConstIterator &operator=(const ConstIterator &p_it) {
+			E = p_it.E;
+			return *this;
+		}
 		ConstIterator(const Element *p_E) { E = p_E; }
 		ConstIterator() {}
 		ConstIterator(const ConstIterator &p_it) { E = p_it.E; }