[clang][DR] Test and mark DR1479 as complete

[zero9178]

Summary

DR: http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1479

Clang has implemented this DR as far back as I could go on compiler explorer (3.0). This patch simply adds a test case and needed comments for the update script to mark it as complete.

[ChuanqiXu]

LGTM.

clang/test/CXX/drs/dr14xx.cpp

 #endif
     f({uR"(abc)"});   // expected-error {{call to deleted function 'f'}}
     f({(UR"(abc)")}); // expected-error {{call to deleted function 'f'}}
   }
   } // namespace StringLiterals
 #endif
 } // dr1467
 
+namespace dr1479 { // dr1479: yes
+  int operator"" _a(const char*, std::size_t = 0); // expected-error {{literal operator cannot have a default argument}}
+}
+
 namespace dr1490 {  // dr1490: 3.7 c++11
   // List-initialization from a string literal
 
   char s[4]{"abc"};                   // Ok
   std::initializer_list<char>{"abc"}; // expected-error {{expected unqualified-id}}}
 } // dr190
 
 namespace dr1495 { // dr1495: 4

clang/www/cxx_dr_status.html

<tr id="1478">
     <td>DRWP</td>
     <td><TT>template</TT> keyword for dependent template template arguments</td>
     <td class="none" align="center">Unknown</td>
   </tr>
   <tr id="1479">
     <td><a href="https://wg21.link/cwg1479">1479</a></td>
     <td>CD3</td>
     <td>Literal operators and default arguments</td>
-    <td class="none" align="center">Unknown</td>
+    <td class="full" align="center">Yes</td>
   </tr>
   <tr id="1480">
     <td><a href="https://wg21.link/cwg1480">1480</a></td>
     <td>CD3</td>
     <td>Constant initialization via non-constant temporary</td>
     <td class="none" align="center">Unknown</td>
   </tr>
   <tr id="1481">