utils: Color is now immutable

as is always the case with mutability, allowing this creates lots of complications that aren't worth the hassle.

changelogs/4.0-snapshot.md

@@ -641,6 +641,10 @@ This version features substantial changes to the network system, improving coher
 - The following API methods have signature changes:
   - `Internet::simpleCurl()` now requires a `Closure` for its `onSuccess` parameter instead of `callable`.
 - The following API methods have been removed:
+  - `Color->setA()`
+  - `Color->setR()`
+  - `Color->setG()`
+  - `Color->setB()`
   - `Color->toABGR()`
   - `Color->toBGRA()`
   - `Color::fromABGR()`

src/pocketmine/utils/Color.php

@@ -53,15 +53,6 @@ class Color{
 		return $this->a;
 	}
 
-	/**
-	 * Sets the alpha (opacity) value of this colour, lower = more transparent
-	 *
-	 * @param int $a
-	 */
-	public function setA(int $a) : void{
-		$this->a = $a & 0xff;
-	}
-
 	/**
 	 * Retuns the red value of this colour.
 	 * @return int
@@ -70,15 +61,6 @@ class Color{
 		return $this->r;
 	}
 
-	/**
-	 * Sets the red value of this colour.
-	 *
-	 * @param int $r
-	 */
-	public function setR(int $r) : void{
-		$this->r = $r & 0xff;
-	}
-
 	/**
 	 * Returns the green value of this colour.
 	 * @return int
@@ -87,15 +69,6 @@ class Color{
 		return $this->g;
 	}
 
-	/**
-	 * Sets the green value of this colour.
-	 *
-	 * @param int $g
-	 */
-	public function setG(int $g) : void{
-		$this->g = $g & 0xff;
-	}
-
 	/**
 	 * Returns the blue value of this colour.
 	 * @return int
@@ -104,15 +77,6 @@ class Color{
 		return $this->b;
 	}
 
-	/**
-	 * Sets the blue value of this colour.
-	 *
-	 * @param int $b
-	 */
-	public function setB(int $b) : void{
-		$this->b = $b & 0xff;
-	}
-
 	/**
 	 * Mixes the supplied list of colours together to produce a result colour.
 	 *