check for missed dbg!() statements

This works in our main code, but doesn't catch dbg!() statements in
our build scripts.

rslib/BUILD.bazel

@@ -138,6 +138,9 @@ rust_test(
         "tests/support/**",
     ]),
     rustc_env = _anki_rustc_env,
+    rustc_flags = [
+        "-Dclippy::dbg_macro",
+    ],
     deps = [
         "//rslib/cargo:env_logger",
         "//rslib/cargo:linkcheck",

rslib/i18n/BUILD.bazel

@@ -60,6 +60,9 @@ rust_library(
 rust_test(
     name = "i18n_tests",
     crate = ":anki_i18n",
+    rustc_flags = [
+        "-Dclippy::dbg_macro",
+    ],
 )
 
 rustfmt_test(