Make Signature.pod6 compilable with small example code fixes

Missed names, semicolons or exception catches.

Author: Altai-man

doc/Type/Signature.pod6

@@ -169,6 +169,7 @@ can be used to that effect.
     sub f(*@a where {$_.all ~~ Int}) { say @a };
     f(42);
     f(<a>);
+    CATCH { default { say .^name, ' ==> ', .Str }  }
     # OUTPUT«[42]␤Constraint type check failed for parameter '@a'␤  in sub f at ...»
 
 =head3 Constraining named Arguments
@@ -245,9 +246,9 @@ has the same function. C<Nil> and its subclasses do B<not> abide by return
 constraints. This allows L<Failure|/type/Failure> to be returned and passed on
 down the call chain.
 
-    sub(--> Int) { my Int $i; $i };
-    sub(--> Int:D) { 1 }
-    sub() returns Int { 1 };
+    sub foo(--> Int) { my Int $i; $i };
+    sub baz(--> Int:D) { 1 }
+    sub bar() returns Int { 1 };
     sub does-not-work(--> Int) { "" }; # throws X::TypeCheck::Return
 
 If the type constraint is a constant expression, it is used as the return value
@@ -345,7 +346,7 @@ dissolving one or more layers of bare C<Iterables>.
     my @array = <a b c>;
     my $list := <d e f>;
     sub a(*@a)  { @a.perl.say };
-    a(@array)                  # ["a", "b", "c"]
+    a(@array);                 # ["a", "b", "c"]
     a(1, $list, [2, 3]);       # [1, "d", "e", "f", 2, 3]
     a([1, 2]);                 # [1, 2]
     a(1, [1, 2], ([3, 4], 5)); # [1, 1, 2, 3, 4 5]