rest-api-config.txt: Fix monospace `plugin`

The previous form `plugin ` renders as literal backticks, not monospace.

Change-Id: I6b261f9897275a7c699b2df0a5e11c8d7eb0a606
diff --git a/Documentation/rest-api-config.txt b/Documentation/rest-api-config.txt
index 4b8922a..3ec989e 100644
--- a/Documentation/rest-api-config.txt
+++ b/Documentation/rest-api-config.txt
@@ -1927,7 +1927,7 @@
 GerritInfo] entity.
 |`note_db_enabled`         |not set if `false`|
 Whether the NoteDb storage backend is fully enabled.
-|`plugin `                 ||
+|`plugin`                  ||
 Information about Gerrit extensions by plugins as
 link:#plugin-config-info[PluginConfigInfo] entity.
 |`receive`                 |optional|