build: Apply buildifier lint and formatting fixes

- Enable parse_headers in root BUILD.bazel.
- Enable layering_check in test/orfs/mock-array/BUILD.
- Remove unused py_library load from src/pdn/test/BUILD.

TAG=agy
CONV=56950afb-bfb2-4074-bfcb-927c5a0f1057

Signed-off-by: Drew Lewis <cannada@google.com>

Author: calewis

BUILD.bazel

@@ -14,7 +14,7 @@ load("//bazel:tcl_wrap_cc.bzl", "tcl_wrap_cc")
 
 package(
     features = [
-        "-parse_headers",
+        "parse_headers",
         "layering_check",
         # TODO(b/299593765): Fix strict ordering.
         "-libcxx_assertions",

src/pdn/test/BUILD

@@ -1,4 +1,4 @@
-load("@rules_python//python:defs.bzl", "py_library", "py_test")
+load("@rules_python//python:defs.bzl", "py_test")
 load("//test:regression.bzl", "doc_check_test", "regression_test")
 
 package(features = ["layering_check"])
@@ -303,7 +303,6 @@ filegroup(
     for test_name in ALL_TESTS
 ]
 
-
 py_test(
     name = "pdn_man_tcl_check",
     srcs = ["pdn_man_tcl_check.py"],

test/orfs/mock-array/BUILD

@@ -3,7 +3,7 @@ load("//test/orfs/asap7:asap7.bzl", "ASAP7_REMOVE_CELLS")
 load(":mock-array.bzl", "config", "element", "mock_array", "verilog")
 
 package(
-    features = ["-layering_check"],  # TODO: enable
+    features = ["layering_check"],  # TODO: enable
 )
 
 exports_files(["write_verilog.tcl"])