docs(lint): add proper newlines

Author: weihanglo

crates/xtask-lint-docs/src/main.rs

@@ -74,7 +74,7 @@ fn main() -> anyhow::Result<()> {
 }
 
 fn add_lint(lint: &Lint, buf: &mut String) -> anyhow::Result<()> {
-    writeln!(buf, "## `{}`", lint.name)?;
+    writeln!(buf, "## `{}`\n", lint.name)?;
     writeln!(buf, "Set to `{}` by default\n", lint.default_level)?;
 
     let src_path = lint_docs_src_path(lint);

src/doc/src/reference/lints.md

@@ -9,6 +9,7 @@ These lints are all set to the 'warn' level by default.
 - [`unknown_lints`](#unknown_lints)
 
 ## `blanket_hint_mostly_unused`
+
 Set to `warn` by default
 
 ### What it does
@@ -41,6 +42,7 @@ hint-mostly-unused = true
 
 
 ## `unknown_lints`
+
 Set to `warn` by default
 
 ### What it does