Add missing period in RUF200 "Why is this bad?" documentation portion (#26930)

Author: jonathandung

crates/ruff_linter/src/rules/ruff/rules/invalid_pyproject_toml.rs

@@ -12,7 +12,7 @@ use crate::{FixAvailability, Violation, checkers::ast::LintContext};
 /// Checks for any pyproject.toml that does not conform to the schema from the relevant PEPs.
 ///
 /// ## Why is this bad?
-/// Your project may contain invalid metadata or configuration without you noticing
+/// Your project may contain invalid metadata or configuration without you noticing.
 ///
 /// ## Example
 /// ```toml