Document dynamic-scope pragma

doc/Language/pragmas.pod6

@@ -74,6 +74,35 @@ pragmas, currently the three above; thus, it would be equivalent to
     use MONKEY-SEE-NO-EVAL;
     use MONKEY-GUTS;
 
+X<dynamic-scope, pragma>
+=head2 dynamic-scope
+
+Applies the L<is dynamic|/type/Variable#trait_is_dynamic> trait to variables
+in the pragma's lexical scope. The effect can be restricted to a subset of
+variables by listing their names as arguments. By default applies to I<all>
+variables.
+
+=begin code :allow<C>
+# Apply C<is dynamic> only to $x, but not to $y
+use dynamic-scope <$x>;
+
+sub poke {
+    say $CALLER::x;
+    say $CALLER::y;
+}
+
+my $x = 23;
+my $y = 34;
+poke;
+
+# OUTPUT:
+# 23
+# Cannot access '$y' through CALLER, because it is not declared as dynamic
+=end code
+
+This pragma is not currently part of any Perl 6 specification and was added
+in Rakudo 2019.03.
+
 X<|experimental, pragma>
 =head2 experimental