Clarify development server URL

Since commit b1b8c4a45d5feb5bd11798a7d8469f7af0f04405, the dev server
uses by default a base path equal to the absolute path of the current
directory.

This CL clarifies this in the developer guide.

Change-Id: I3c609736008760fad5748244960d82ca7595a590

Documentation/developer-guide.md

diff --git a/Documentation/developer-guide.md b/Documentation/developer-guide.md
index d36a24d..0a96b3a 100644
--- a/Documentation/developer-guide.md
+++ b/Documentation/developer-guide.md
@@ -67,8 +67,8 @@
 ```
 
 This will recompile and start a development server.  Open
-http://localhost:8080/ to view your local copy of gitiles, which
-will serve any repositories under `/path/to/repositories`.
+http://localhost:8080/path/to/repositories to view your local copy of gitiles,
+which will serve any repositories under `/path/to/repositories`.
 
 Passing `--debug` option to `tools/run_dev.sh` will suspend the runtime until a
 remote debugger connects to port 5005. If you don't want to suspend the