fix: port_rule has_number for port zero at end of input

Author: alandefreitas

include/boost/url/rfc/detail/impl/port_rule.hpp

@@ -68,7 +68,7 @@ parse(
     }
     // no digits
     t.str = core::string_view(start, it);
-    t.has_number = it != end;
+    t.has_number = it != start;
     t.number = 0;
     return t;
 }

test/unit/rfc/authority_rule.cpp

@@ -64,6 +64,27 @@ class authority_rule_test
                         a.encoded_password(), "y");
             }
         }
+
+        // port zero at end of input
+        // (has_number regression)
+        {
+            auto rv = grammar::parse(
+                "host:0", authority_rule);
+            if(BOOST_TEST(rv.has_value()))
+            {
+                BOOST_TEST(rv->has_port());
+                BOOST_TEST_EQ(rv->port_number(), 0);
+            }
+        }
+        {
+            auto rv = grammar::parse(
+                "host:000", authority_rule);
+            if(BOOST_TEST(rv.has_value()))
+            {
+                BOOST_TEST(rv->has_port());
+                BOOST_TEST_EQ(rv->port_number(), 0);
+            }
+        }
     }
 };