Fix DL_WARN_documented_change URL

The doc_link argument is really a URL fragment within the
android-changes-for-ndk-developers.md document, not a filename at the
root of the bionic repository.

Test: manual
Bug: none
Change-Id: I1b542e47aca132ce43ba1d50d83db1bf3c7b10c6
diff --git a/linker/linker.cpp b/linker/linker.cpp
index bf75178..ac83cae 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -3273,9 +3273,8 @@
     // Fail if app is targeting M or above.
     int app_target_api_level = get_application_target_sdk_version();
     if (app_target_api_level >= 23) {
-      DL_ERR_AND_LOG("\"%s\" has text relocations (https://android.googlesource.com/platform/"
-                     "bionic/+/master/android-changes-for-ndk-developers.md#Text-Relocations-"
-                     "Enforced-for-API-level-23)", get_realpath());
+      DL_ERR_AND_LOG("\"%s\" has text relocations (%s#Text-Relocations-Enforced-for-API-level-23)",
+                     get_realpath(), kBionicChangesUrl);
       return false;
     }
     // Make segments writable to allow text relocations to work properly. We will later call