Update the status of some C2x features

Only N2670 had testable changes in it, the rest can be trivially
assumed to be implemented as the changes are editorial.

clang/test/C/C2x/n2670.c

@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -std=c2x -verify %s
+// expected-no-diagnostics
+
+/* WG14 N2670: yes
+ * Zeros compare equal
+ */
+_Static_assert(-1 * 0.0 == 0.0, "");
+_Static_assert(!(-1 * 0.0 < 0.0), "");

clang/www/c_status.html

@@ -850,7 +850,7 @@ conformance.</p>
     <tr>
       <td>Missing +(x) in table</td>
       <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2641.htm">N2641</a></td>
-      <td class="unknown" align="center">Unknown</td>
+      <td class="full" align="center">Yes</td>
     </tr>
     <tr>
       <td>Add support for preprocessing directives elifdef and elifndef</td>
@@ -866,7 +866,7 @@ conformance.</p>
     <tr>
       <td>Zeros compare equal</td>
       <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2670.pdf">N2670</a></td>
-      <td class="unknown" align="center">Unknown</td>
+      <td class="full" align="center">Yes</td>
     </tr>
     <tr>
       <td>Negative values</td>
@@ -916,7 +916,7 @@ conformance.</p>
     <tr>
       <td>Numerically equal</td>
       <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2716.htm">N2716</a></td>
-      <td class="unknown" align="center">Unknown</td>
+      <td class="full" align="center">Yes</td>
     </tr>
     <tr>
       <td>char16_t & char32_t string literals shall be UTF-16 & UTF-32</td>
@@ -1058,7 +1058,7 @@ conformance.</p>
     <tr>
       <td>Revised Suggestions of Change for Numerically Equal/Equivalent</td>
       <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2847.pdf">N2847</a></td>
-      <td class="unknown" align="center">Unknown</td>
+      <td class="full" align="center">Yes</td>
     </tr>
     <tr>
       <td>5.2.4.2.2 Cleanup, Again Again (N2806 update)</td>