Make user.bazelrc relative to workspace root

Closes #15688.

PiperOrigin-RevId: 470988978
Change-Id: Ic4c0711bf28225912f7c7ba34f63c7e11b978398
diff --git a/.bazelrc b/.bazelrc
index f3d08f6..20921ea 100644
--- a/.bazelrc
+++ b/.bazelrc
@@ -35,6 +35,6 @@
 build --tool_java_language_version=11
 
 # User-specific .bazelrc
-try-import user.bazelrc
+try-import %workspace%/user.bazelrc
 
 build:docs --workspace_status_command=scripts/docs/get_workspace_status.sh