rename love_Canvases to love_RenderTargets in shaders.

More misc. renaming

src/modules/graphics/Graphics.h

@@ -133,9 +133,9 @@ public:
 
 	enum Feature
 	{
-		FEATURE_MULTI_CANVAS_FORMATS,
+		FEATURE_MULTI_RENDER_TARGET_FORMATS,
 		FEATURE_CLAMP_ZERO,
-		FEATURE_BLENDMINMAX,
+		FEATURE_BLEND_MINMAX,
 		FEATURE_LIGHTEN, // Deprecated
 		FEATURE_FULL_NPOT,
 		FEATURE_PIXEL_SHADER_HIGHP,
@@ -160,8 +160,8 @@ public:
 		LIMIT_VOLUME_TEXTURE_SIZE,
 		LIMIT_CUBE_TEXTURE_SIZE,
 		LIMIT_TEXTURE_LAYERS,
-		LIMIT_MULTI_CANVAS,
-		LIMIT_CANVAS_MSAA,
+		LIMIT_RENDER_TARGETS,
+		LIMIT_TEXTURE_MSAA,
 		LIMIT_ANISOTROPY,
 		LIMIT_MAX_ENUM
 	};