doc: Fix "lazy continuation" in slog::Logger

This is a mistake in markdown syntax, caught by a clippy lint:
https://rust-lang.github.io/rust-clippy/rust-1.81.0/index.html#/doc_lazy_continuation

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
+* doc: Fix "lazy continuation" in `slog::Logger` doc
+  * This mistake was caught by a new lint [`#[warn(clippy::doc_lazy_continuation)]`](https://rust-lang.github.io/rust-clippy/rust-1.81.0/index.html#/doc_lazy_continuation)
 * Fix some internal warnings
   * Example: Avoid the new [`#[warn(unexpected_cfgs)]`](https://blog.rust-lang.org/2024/05/06/check-cfg.html) lint.
   * None of these should affect user crates

src/lib.rs

@@ -1069,7 +1069,7 @@ macro_rules! __slog_builtin {
 /// In an essence `Logger` instance holds two pieces of information:
 ///
 /// * drain - destination where to forward logging `Record`s for
-/// processing.
+///   processing.
 /// * context - list of key-value pairs associated with it.
 ///
 /// The root `Logger` is created with a `Drain` that will be cloned to every