Apply suggestions from code review

Co-authored-by: Erik Ernst <eernst@google.com>

src/content/language/generics.md

@@ -196,7 +196,7 @@ Specifying any non-`SomeBaseClass` type results in an error:
 var foo = [!Foo<Object>!]();
 ```
 
-### Self-referential type parameter restrictions
+### Self-referential type parameter restrictions (F-bounds)
 
 When using bounds to restrict parameter types, you can refer the bound
 back to the type parameter itself. This creates a self-referential constraint,

src/content/language/type-system.md

@@ -379,7 +379,7 @@ Inference using bounds requires a [language version][] of at least 3.7.0.
 :::
 
 Dart's type inference algorithm generates constraints by combining
-exisiting lower-bound constraints with the actual type bounds,
+existing lower-bound constraints with the actual type bounds,
 not just best-effort approximations.
 This is especially important for [F-bounded][] types,
 where inference using bounds correctly infers that, in the example below,