Fix API name in document scan

BUG=450601
R=kalman@chromium.org

Review URL: https://codereview.chromium.org/901583003

Cr-Commit-Position: refs/heads/master@{#314710}

chrome/common/extensions/api/document_scan.idl

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Use the <code>chrome.document_scan</code> API to discover and retrieve
+// Use the <code>chrome.documentScan</code> API to discover and retrieve
 // images from attached paper document scanners.
 namespace documentScan {
   dictionary ScanOptions {