Fix spelling mistakes in comments.

components/layout/floats.rs

@@ -237,7 +237,7 @@ impl Floats {
 
         // FIXME(eatkinson): This assertion is too strong and fails in some cases. It is OK to
         // return negative inline-sizes since we check against that inline-end away, but we should
-        // still undersrtand why they occur and add a stronger assertion here.
+        // still understand why they occur and add a stronger assertion here.
         // assert!(max_inline-start < min_inline-end);
 
         assert!(block_start <= block_end, "Float position error");

components/layout/inline.rs

@@ -128,7 +128,7 @@ pub struct Line {
     /// ~~~
     pub bounds: LogicalRect<Au>,
 
-    /// The green zone is the greatest extent from wich a line can extend to
+    /// The green zone is the greatest extent from which a line can extend to
     /// before it collides with a float.
     ///
     /// ~~~text
@@ -307,7 +307,7 @@ impl LineBreaker {
         let splittable = first_fragment.can_split();
         debug!("LineBreaker: fragment size: {}, splittable: {}", first_fragment_size, splittable);
 
-        // Initally, pretend a splittable fragment has zero inline-size. We will move it later if
+        // Initially, pretend a splittable fragment has zero inline-size. We will move it later if
         // it has nonzero inline-size and that causes problems.
         let placement_inline_size = if splittable {
             Au(0)

components/layout/text.rs

@@ -250,7 +250,7 @@ fn bounding_box_for_run_metrics(metrics: &RunMetrics, writing_mode: WritingMode)
         None => {}
     }
 
-    // In vertical sideways or horizontal upgright text,
+    // In vertical sideways or horizontal upright text,
     // the "width" of text metrics is always inline
     // This will need to be updated when other text orientations are supported.
     LogicalSize::new(