add crate doc to examples

crates/servicepoint/examples/announce.rs

@@ -1,3 +1,5 @@
+//! An example for how to send text to the display.
+
 use clap::Parser;
 
 use servicepoint::{ByteGrid, Command, Connection, Grid, Origin};

crates/servicepoint/examples/game_of_life.rs

@@ -1,3 +1,5 @@
+//! A simple game of life implementation to show how to render graphics to the display.
+
 use std::thread;
 
 use clap::Parser;

crates/servicepoint/examples/moving_line.rs

@@ -1,3 +1,5 @@
+//! A simple example for how to send pixel data to the display.
+
 use std::thread;
 
 use clap::Parser;

crates/servicepoint/examples/random_brightness.rs

@@ -1,3 +1,6 @@
+//! A simple example for how to set brightnesses for tiles on the screen.
+//! Continuously changes the tiles in a random window to random brightnesses.
+
 use std::time::Duration;
 
 use clap::Parser;

crates/servicepoint/examples/wiping_clear.rs

@@ -1,3 +1,4 @@
+//! An example on how to modify the image on screen without knowing the current content.
 use std::thread;
 use std::time::Duration;