Fix typos (#1608)

src/chromium/testing.md

@@ -39,7 +39,7 @@ used:
 
 * QR has very little functionality in the first-party Rust layer (it's just a
   thin FFI glue) and therefore uses the existing C++ unit tests for testing
-  both the C++ and the Rust implementation (parametrizing the tests so they
+  both the C++ and the Rust implementation (parameterizing the tests so they
   enable or disable Rust using a `ScopedFeatureList`).
 
 * Hypothetical/WIP PNG integration may need to implement memory-safe

src/hello-world/playground.md

@@ -24,6 +24,6 @@ few handy features:
 As students head into the break, encourage them to open up the playground and
 experiment a little. Encourage them to keep the tab open and try things out
 during the rest of the course. This is particularly helpful for advanced
-students who want to know more about Rust's optimzations or generated assembly.
+students who want to know more about Rust's optimizations or generated assembly.
 
 </details>

src/std-traits/operators.md

@@ -36,7 +36,7 @@ Discussion points:
         call site.
 * Why is `Output` an associated type? Could it be made a type parameter of the method?
     * Short answer: Function type parameters are controlled by the caller, but
-        associated types (like `Output`) are controlled by the implementor of a
+        associated types (like `Output`) are controlled by the implementer of a
         trait.
 * You could implement `Add` for two different types, e.g.
   `impl Add<(i32, i32)> for Point` would add a tuple to a `Point`.

src/unsafe-rust/dereferencing.md

@@ -51,7 +51,7 @@ In the case of pointer dereferences, this means that the pointers must be
 
 In most cases the pointer must also be properly aligned.
 
-The "NOT SAFE" sectoin gives an example of a common kind of UB bug: `*r1` has
+The "NOT SAFE" section gives an example of a common kind of UB bug: `*r1` has
 the `'static` lifetime, so `r3` has type `&'static String`, and thus outlives
 `s`. Creating a reference from a pointer requires _great care_.
 

theme/speaker-notes.js

@@ -206,7 +206,7 @@
         }
         break;
       case "speakerNotes":
-        // When nagigating to another page, we see two state changes in rapid
+        // When navigating to another page, we see two state changes in rapid
         // succession:
         //
         // - "popup" -> "inline-open"