Format bazel build files with buildifier.

github.com//issues/122

Author: ChrisCummins

programl/graph/format/BUILD

@@ -111,7 +111,7 @@ cc_test(
         "//programl/proto:program_graph_cc",
         "@labm8//labm8/cpp:status",
         "@labm8//labm8/cpp:test",
-    ]
+    ],
 )
 
 cc_library(

programl/graph/py/BUILD

@@ -36,8 +36,8 @@ py_library(
     data = [":program_graph_builder_pybind.so"],
     visibility = ["//visibility:public"],
     deps = [
-        "//programl/proto:program_graph_py",
         "//programl/proto:program_graph_options_py",
+        "//programl/proto:program_graph_py",
     ],
 )
 
@@ -48,8 +48,8 @@ py_test(
         ":program_graph_builder",
         "//programl/proto:edge_py",
         "//programl/proto:node_py",
-        "//programl/proto:program_graph_py",
         "//programl/proto:program_graph_options_py",
+        "//programl/proto:program_graph_py",
         "//third_party/py/labm8",
     ],
 )