[css-fonts-4] Spec doesn't mention "woff2" anywhere

Adding format() specifiers for woff2 and woff2-variations.

Author: litherum

css-fonts-4/Overview.bs

@@ -1369,6 +1369,11 @@ at least as dark as its predecessor. Only values greater than 0 and less than 10
 			  <td><a href="https://www.microsoft.com/typography/otspec/default.htm">OpenType</a></td>
 			  <td>.ttf, .otf</td>
 			</tr>
+			<tr>
+			  <th>"woff2"</th>
+			  <td><a href="https://www.w3.org/TR/WOFF2/">WOFF File Format 2.0 (Web Open Font Format)</a></td>
+			  <td>.woff2</td>
+			</tr>
 			<tr>
 			  <th>"embedded-opentype"</th>
 			  <td><a href="https://www.w3.org/Submission/2008/SUBM-EOT-20080305/">Embedded OpenType</a></td>
@@ -1394,6 +1399,11 @@ at least as dark as its predecessor. Only values greater than 0 and less than 10
 			  <td><a href="https://www.microsoft.com/typography/otspec/default.htm">OpenType with associated variations support</a></td>
 			  <td>.ttf, .otf</td>
 			</tr>
+			<tr>
+			  <th>"woff2-variations"</th>
+			  <td><a href="https://www.w3.org/TR/WOFF2/">WOFF File Format 2.0 (Web Open Font Format) with associated variations support</a></td>
+			  <td>.woff2</td>
+			</tr>
 		</tbody>
 	</table>
 
@@ -1403,8 +1413,8 @@ at least as dark as its predecessor. Only values greater than 0 and less than 10
 	Postscript CFF style glyph data or that it contains OpenType layout
 	information (see <a href="#platform-props-to-css">Appendix A</a> for more background on this).
 
-	A value of "woff-variations", "truetype-variations", or "opentype-variations" imply support
-	of the "woff", "truetype", or "opentype" formats respectively along with additional support for
+	A value of "woff-variations", "truetype-variations", "opentype-variations", or "woff2-variations" imply support
+	of the "woff", "truetype", "opentype", or "woff2" formats respectively along with additional support for
 	font variations. Web authors can specify this format to indicate that variation support is required
 	for correct rendering of a font. This mechanism can be used for gracefully falling back to an
 	ancillary font when variation support is not present.