Move loads to beginning of BUILD files.

Change-Id: Idb918a48cfe6149f624295f6712fbf0a3a36a7ff
diff --git a/pw_dumb_io/BUILD b/pw_dumb_io/BUILD
index 5fe691e..8689b39 100644
--- a/pw_dumb_io/BUILD
+++ b/pw_dumb_io/BUILD
@@ -12,15 +12,15 @@
 # License for the specific language governing permissions and limitations under
 # the License.
 
-package(default_visibility = ["//visibility:public"])
-
-licenses(["notice"])
-
 load(
     "//pw_build:pigweed.bzl",
     "pw_cc_library",
 )
 
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
 pw_cc_library(
     name = "pw_dumb_io",
     srcs = ["dumb_io.cc"],
diff --git a/pw_preprocessor/BUILD b/pw_preprocessor/BUILD
index 206521d..be20566 100644
--- a/pw_preprocessor/BUILD
+++ b/pw_preprocessor/BUILD
@@ -12,16 +12,16 @@
 # License for the specific language governing permissions and limitations under
 # the License.
 
-package(default_visibility = ["//visibility:public"])
-
-licenses(["notice"])  # Apache License 2.0
-
 load(
     "//pw_build:pigweed.bzl",
     "pw_cc_library",
     "pw_cc_test",
 )
 
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])  # Apache License 2.0
+
 pw_cc_library(
     name = "pw_preprocessor",
     hdrs = glob(["public/pw_preprocessor/*.h"]),
diff --git a/pw_span/BUILD b/pw_span/BUILD
index ea21100..a163e5f 100644
--- a/pw_span/BUILD
+++ b/pw_span/BUILD
@@ -12,16 +12,16 @@
 # License for the specific language governing permissions and limitations under
 # the License.
 
-package(default_visibility = ["//visibility:public"])
-
-licenses(["notice"])  # Apache License 2.0
-
 load(
     "//pw_build:pigweed.bzl",
     "pw_cc_library",
     "pw_cc_test",
 )
 
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])  # Apache License 2.0
+
 pw_cc_library(
     name = "pw_span",
     srcs = [],
diff --git a/pw_status/BUILD b/pw_status/BUILD
index e381e07..34bb50c 100644
--- a/pw_status/BUILD
+++ b/pw_status/BUILD
@@ -12,16 +12,16 @@
 # License for the specific language governing permissions and limitations under
 # the License.
 
-package(default_visibility = ["//visibility:public"])
-
-licenses(["notice"])  # Apache License 2.0
-
 load(
     "//pw_build:pigweed.bzl",
     "pw_cc_library",
     "pw_cc_test",
 )
 
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])  # Apache License 2.0
+
 pw_cc_library(
     name = "pw_status",
     srcs = ["status.cc"],
diff --git a/pw_string/BUILD b/pw_string/BUILD
index 8959ea1..3351fdc 100644
--- a/pw_string/BUILD
+++ b/pw_string/BUILD
@@ -12,16 +12,16 @@
 # License for the specific language governing permissions and limitations under
 # the License.
 
-package(default_visibility = ["//visibility:public"])
-
-licenses(["notice"])  # Apache License 2.0
-
 load(
     "//pw_build:pigweed.bzl",
     "pw_cc_library",
     "pw_cc_test",
 )
 
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])  # Apache License 2.0
+
 pw_cc_library(
     name = "pw_string",
     srcs = [
diff --git a/pw_unit_test/BUILD b/pw_unit_test/BUILD
index c5a87e4..8e5c214 100644
--- a/pw_unit_test/BUILD
+++ b/pw_unit_test/BUILD
@@ -12,16 +12,16 @@
 # License for the specific language governing permissions and limitations under
 # the License.
 
-package(default_visibility = ["//visibility:public"])
-
-licenses(["notice"])  # Apache License 2.0
-
 load(
     "//pw_build:pigweed.bzl",
     "pw_cc_library",
     "pw_cc_test",
 )
 
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])  # Apache License 2.0
+
 pw_cc_library(
     name = "simple_printing_event_handler",
     srcs = [