[glossary.pod] Fixed a couple of errors spotted by raiph++

Fixed two typos and s/native/builtin/ in an example, because there are
no native 'str's.

lib/glossary.pod

@@ -43,12 +43,12 @@ I<autothreading>.
 
 An I<instance> of a class is also called an I<object> in some other
 programming languages. It has a storage for attributes, and is often
-the return value of a class to a method called C<new>, or a literal.
+the return value of a call to a method called C<new>, or a literal.
 
 Instances of most types are defined to be C<True>
 i.e., C<defined($instance)> is C<True>.
 
-    my Str $str = "hello";  ## this is with native types. Str
+    my Str $str = "hello";  ## this is with builtin types, e.g. Str
     if defined($str) {
         say "Oh, yeah. I'm defined.";
     } else {
@@ -103,11 +103,11 @@ Examples of lvalues:
 
 Examples of things that are not lvalues
 
-   3                        # literal s
-   constant x = 3;          # constants
-   has $.attrib;            # attributes; you can only assign to $!attrib
-   sub f { }; f();          # "normal" subs are not writable
-   sub f($x) { $x = 3 };    # error - parameters are read-only by default
+    3                        # literals
+    constant x = 3;          # constants
+    has $.attrib;            # attributes; you can only assign to $!attrib
+    sub f { }; f();          # "normal" subs are not writable
+    sub f($x) { $x = 3 };    # error - parameters are read-only by default
 
 
 =head1 Slurpy