[Fuchsia] Rename additional_manifests to additional_manifest_fragments

Replace incorrect name of manifests to manifest fragments.

Bug: 1187357
Change-Id: I4a9d42eb96eba20059cef682a1934b0e7c4d9359
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2787981
Auto-Submit: Chong Gu <chonggu@google.com>
Reviewed-by: danakj <danakj@chromium.org>
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Chong Gu <chonggu@google.com>
Cr-Commit-Position: refs/heads/master@{#867665}

diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index 790905f..13098ad0 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn

@@ -861,7 +861,7 @@
   ]
 
   if (is_fuchsia) {
-    additional_manifests = [
+    additional_manifest_fragments = [
       "//build/config/fuchsia/test/font_capabilities.test-cmx",
 
       # TODO(crbug.com/1185811): Figure out why jit_capabilities is needed.