Consistent capitalization for deprecated function names in documentation (#1567)

Author: yttersian

src/lib.rs

@@ -114,7 +114,7 @@ pub use crate::rngs::thread::rng;
 ///
 /// Use [`rand::rng()`](rng()) instead.
 #[cfg(feature = "thread_rng")]
-#[deprecated(since = "0.9.0", note = "renamed to `rng`")]
+#[deprecated(since = "0.9.0", note = "Renamed to `rng`")]
 #[inline]
 pub fn thread_rng() -> crate::rngs::ThreadRng {
     rng()