add SkParagraph to public headers and fix warnings

Change-Id: Icb62636e96f1fecb97c4f4c918d073ab611420f3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/302900
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Julia Lavrova <jlavrova@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index d07e57a..627595d 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1286,6 +1286,7 @@
     "include/svg",
     "include/utils",
     "include/utils/mac",
+    "modules/skparagraph/include",
     "modules/skshaper/include",
     "modules/skottie/include",
   ]