add missing word in doc comment

src/bootstrap/src/core/builder/mod.rs

@@ -101,13 +101,13 @@ pub trait Step: 'static + Clone + Debug + PartialEq + Eq + Hash {
     /// Primary function to implement `Step` logic.
     ///
     /// This function can be triggered in two ways:
-    ///     1. Directly from [`Builder::execute_cli`].
-    ///     2. Indirectly by being called from other `Step`s using [`Builder::ensure`].
+    /// 1. Directly from [`Builder::execute_cli`].
+    /// 2. Indirectly by being called from other `Step`s using [`Builder::ensure`].
     ///
-    /// When called with [`Builder::execute_cli`] (as done by `Build::build`), this function executed twice:
-    ///     - First in "dry-run" mode to validate certain things (like cyclic Step invocations,
-    ///         directory creation, etc) super quickly.
-    ///     - Then it's called again to run the actual, very expensive process.
+    /// When called with [`Builder::execute_cli`] (as done by `Build::build`), this function is executed twice:
+    /// - First in "dry-run" mode to validate certain things (like cyclic Step invocations,
+    ///   directory creation, etc) super quickly.
+    /// - Then it's called again to run the actual, very expensive process.
     ///
     /// When triggered indirectly from other `Step`s, it may still run twice (as dry-run and real mode)
     /// depending on the `Step::run` implementation of the caller.