Fix typo "immediatelly" → "immediately"

src/core/Date.pm6

@@ -213,7 +213,7 @@ proto sub sleep($?, *%) {*}
 multi sub sleep(--> Nil) { sleep(*) }
 multi sub sleep($seconds --> Nil) {
     # 1e9 seconds is a large enough value that still makes VMs sleep
-    # larger values cause nqp::sleep() to exit immediatelly (esp. on 32-bit)
+    # larger values cause nqp::sleep() to exit immediately (esp. on 32-bit)
     if nqp::istype($seconds,Whatever) || $seconds == Inf {
         nqp::sleep(1e9) while True;
     }

src/core/Exception.pm6

@@ -2161,7 +2161,7 @@ my class X::ControlFlow::Return is X::ControlFlow {
     method message()   {
         'Attempt to return outside of ' ~ (
             $!out-of-dynamic-scope
-              ?? 'immediatelly-enclosing Routine (i.e. `return` execution is'
+              ?? 'immediately-enclosing Routine (i.e. `return` execution is'
                ~ ' outside the dynamic scope of the Routine where `return` was used)'
               !! 'any Routine'
         )