update docs and added support to print String from heapless

arduboy-rust/src/library/arduboy2.rs

@@ -346,6 +346,7 @@ impl Arduboy2 {
     ///
     /// arduboy.print(b"Hello World\n\0"[..]); // Prints "Hello World" and then sets the
     ///                                        // text cursor to the start of the next line
+    /// arduboy.print(f!(b"Hello World\n")); // Prints "Hello World" but does not use the 2kb ram
     /// arduboy.print(value); // Prints "42"
     /// arduboy.print("\n\0"); // Sets the text cursor to the start of the next line
     /// arduboy.print("hello world") // Prints normal [&str]

arduboy-rust/src/library/progmem.rs

@@ -110,7 +110,7 @@ pub(super) use get_string_addr;
 /// This automatically saves the given text to the Progmem.
 /// ## Example
 /// ```
-/// arduboy.print(f!(b"Random text to print"))
+/// arduboy.print(f!(b"Random text to print\0"))
 /// ```
 #[macro_export]
 macro_rules! f {

arduboy-rust/src/print.rs

@@ -102,6 +102,17 @@ impl Printable for &str {
 
     fn default_parameters() -> Self::Parameters {}
 }
+impl<const N: usize> Printable for crate::heapless::String<N> {
+    type Parameters = ();
+
+    fn print_2(self, _params: Self::Parameters) {
+        unsafe {
+            crate::library::arduboy2::print_chars(self.as_bytes() as *const [u8] as *const i8);
+        }
+    }
+
+    fn default_parameters() -> Self::Parameters {}
+}
 
 impl Printable for Pstring {
     type Parameters = ();