Update the dev-bazel doc for classpath refreshing of IntelliJ.

Change-Id: I3da34ff05d5c708d7857c3f5d3ff4bcf9d9b2708

Documentation/dev-bazel.txt

diff --git a/Documentation/dev-bazel.txt b/Documentation/dev-bazel.txt
index a881e3d..d942d9b 100644
--- a/Documentation/dev-bazel.txt
+++ b/Documentation/dev-bazel.txt
@@ -155,7 +155,8 @@
 
 If an updated classpath is needed, the Eclipse project can be
 refreshed and missing dependency JARs can be downloaded by running
-`project_bzl.py` again.
+`project_bzl.py` again. For IntelliJ, you need to click the `Sync Project
+with BUILD Files` button of link:https://ij.bazel.io[IntelliJ plugin].
 
 [[documentation]]
 === Documentation