Fix some broken regexes for files in pre-commit configs. (#2438)

The result was we weren't actually running buildifier on files for
example, so this also runs it on a bunch of files to clean things up.

migrate_cpp/BUILD

@@ -25,6 +25,10 @@ cc_library(
     name = "rewriter",
     srcs = ["rewriter.cpp"],
     hdrs = ["rewriter.h"],
+    visibility = [
+        # For dependency checking. Remove once it has a binary using it.
+        "//bazel/check_deps:__pkg__",
+    ],
     deps = [
         ":output_segment",
         "//common:check",
@@ -36,10 +40,6 @@ cc_library(
         "@llvm-project//clang:tooling_core",
         "@llvm-project//llvm:Support",
     ],
-    visibility = [
-      # For dependency checking. Remove once it has a binary using it.
-      "//bazel/check_deps:__pkg__",
-    ],
 )
 
 cc_test(