Add GenImageGradientSquare (#3077)

* Add GenImageGradientSquare to allow square gradients

* Fix GenImageGradientSquare and add to textures_image_generation example

* Remove params from GenImageGradientSquare

parser/output/raylib_api.json

@@ -6242,7 +6242,7 @@
     },
     {
       "name": "GenImageGradientLinear",
-      "description": "Generate image: linear gradient",
+      "description": "Generate image: linear gradient, direction in degrees [0..360], 0=Vertical gradient",
       "returnType": "Image",
       "params": [
         {
@@ -6294,6 +6294,33 @@
         }
       ]
     },
+    {
+      "name": "GenImageGradientSquare",
+      "description": "Generate image: square gradient",
+      "returnType": "Image",
+      "params": [
+        {
+          "type": "int",
+          "name": "width"
+        },
+        {
+          "type": "int",
+          "name": "height"
+        },
+        {
+          "type": "float",
+          "name": "density"
+        },
+        {
+          "type": "Color",
+          "name": "inner"
+        },
+        {
+          "type": "Color",
+          "name": "outer"
+        }
+      ]
+    },
     {
       "name": "GenImageChecked",
       "description": "Generate image: checked",