Fix linter issues

cpp/src/arrow/array.h

@@ -397,7 +397,6 @@ class ARROW_EXPORT PrimitiveArray : public FlatArray {
   const uint8_t* raw_values_;
 };
 
-
 /// Concrete Array class for numeric data.
 template <typename TYPE>
 class ARROW_EXPORT NumericArray : public PrimitiveArray {

docker-compose.yml

@@ -178,6 +178,8 @@ services:
 
   clang-format:
     # Usage:
+    #   docker-compose build cpp
+    #   docker-compose build python
     #   docker-compose build lint
     #   docker-compose run clang-format
     image: arrow:lint

python/doc/source/conf.py

@@ -30,7 +30,6 @@
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
 #
-import glob
 import os
 import sys
 
@@ -78,7 +77,7 @@ napoleon_use_rtype = False
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
 
-breathe_projects = { "arrow_cpp": "../../../cpp/apidoc/xml" }
+breathe_projects = {"arrow_cpp": "../../../cpp/apidoc/xml"}
 breathe_default_project = "arrow_cpp"
 
 # The suffix(es) of source filenames.