Bump rust-by-example submodule

bstrie · bstrie · commit c2eeadcbe643 · 2022-01-28T12:32:14.000-05:00
This is a necessary prerequisite of rust-lang#92611, to make a new page exist and satisfy the link checker.
diff --git a/src/doc/rust-by-example b/src/doc/rust-by-example
@@ -1 +1 @@
-Subproject commit 1ca6a7bd1d73edc4a3e6c7d6a40f5d4b66c1e517
+Subproject commit 18c0055b8aea49391e8f758a4400097999c9cf1e
