Rust: Add methods to Flavour to get each colour

This adds method to get each of the colors directly from the `Flavour`
variants like so
```rust
Flavour::Latte.teal()
```
rather than needing to go through the `FlavourColours` struct

This closes #27

rust/src/colour.rs

@@ -13,7 +13,7 @@ impl Colour {
     /// ```
     /// use catppuccin::Flavour;
     ///
-    /// let hex = Flavour::Mocha.colours().teal.hex();
+    /// let hex = Flavour::Mocha.teal().hex();
     /// assert_eq!(hex, "94E2D5");
     /// ```
     pub fn hex(&self) -> String {

rust/src/flavour.rs

@@ -8,6 +8,21 @@ pub enum Flavour {
     Mocha,
 }
 
+macro_rules! impl_colour_method {
+    ($x:ident) => (
+        pub fn $x(self) -> $crate::Colour {
+            self.colours().$x
+        }
+    );
+    ($x:ident, $($y:ident),+ $(,)?) => (
+        pub fn $x(self) -> $crate::Colour {
+            self.colours().$x
+        }
+
+        impl_colour_method!($($y),+);
+    );
+}
+
 impl Flavour {
     pub fn name(self) -> &'static str {
         match self {
@@ -18,6 +33,12 @@ impl Flavour {
         }
     }
 
+    impl_colour_method!(
+        rosewater, flamingo, pink, mauve, red, maroon, peach, yellow, green, teal, sky, sapphire,
+        blue, lavender, text, subtext1, subtext0, overlay2, overlay1, overlay0, surface2, surface1,
+        surface0, base, mantle, crust,
+    );
+
     pub fn colours(self) -> FlavourColours {
         match self {
             Self::Latte => FlavourColours {

rust/src/lib.rs

@@ -22,7 +22,7 @@
 //! fn confirm(text: String) -> Button {
 //!     Button {
 //!         text,
-//!         background_colour: Flavour::Mocha.colours().green.hex(),
+//!         background_colour: Flavour::Mocha.green().hex(),
 //!     }
 //! }
 //! ```