implement text support in canvas widget

wgpu/src/widget/canvas/text.rs

@@ -0,0 +1,20 @@
+use iced_native::{Color, Font, HorizontalAlignment, Rectangle, VerticalAlignment};
+
+/// A text node to be drawn to a canvas
+#[derive(Debug, Clone)]
+pub struct TextNode {
+    /// The contents of the text
+    pub content: String,
+    /// The bounds of the text
+    pub bounds: Rectangle,
+    /// The color of the text
+    pub color: Color,
+    /// The size of the text
+    pub size: f32,
+    /// The font of the text
+    pub font: Font,
+    /// The horizontal alignment of the text
+    pub horizontal_alignment: HorizontalAlignment,
+    /// The vertical alignment of the text
+    pub vertical_alignment: VerticalAlignment,
+}