doc: fix spelling in editor guide

Change-Id: If16f069f410d043fd11864a4c1a7d54b5b4922d2
Reviewed-on: https://go-review.googlesource.com/82200Reviewed-by: Ian Lance Taylor <iant@golang.org>

doc/editors.html

@@ -58,7 +58,7 @@ The following feature matrix lists and compares the most significant features.
     <td class="yes">Yes</td>
   </tr>
   <tr>
-    <td>Autocompletion of identifers (variable, method, and function names)</td>
+    <td>Autocompletion of identifiers (variable, method, and function names)</td>
     <td class="yes">Yes</td>
     <td class="yes">Yes</td>
     <td class="yes">Yes</td>