Fixed various typos in a lot of files

Closes https://github.com/dart-lang/sdk/pull/49478

TEST=Manual

GitOrigin-RevId: f4c9c6869dfe73639295e86574a021523b3d374d
Change-Id: I134a97caed4eec59d70e9cbca16b7e9a472cf2c1
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/251902
Reviewed-by: Michael Thomsen <mit@google.com>
Commit-Queue: Alexander Thomas <athom@google.com>
Reviewed-by: Aske Simon Christensen <askesc@google.com>
Reviewed-by: Kevin Chisholm <kevinjchisholm@google.com>
Reviewed-by: Alexander Thomas <athom@google.com>

samples/ffi/sample_ffi_functions_structs.dart

@@ -44,7 +44,7 @@ main() {
   }
 
   {
-    // Pass an array of structs to a c funtion.
+    // Pass an array of structs to a c function.
     Pointer<NativeFunction<NativeCoordinateOp>> p1 =
         ffiTestFunctions.lookup("CoordinateElemAt1");
     NativeCoordinateOp f1 = p1.asFunction();