Add support for reorder-python-imports fixer

isort is great, but I've come to prefer reorder-python-imports. The tool
has a focus on smaller diffs than isort. reorder-python-imports is also
a little smarter than isort which is nice.

autoload/ale/fix/registry.vim

@@ -310,6 +310,11 @@ let s:default_registry = {
 \       'suggested_filetypes': ['sql'],
 \       'description': 'A PostgreSQL SQL syntax beautifier',
 \   },
+\   'reorder-python-imports': {
+\       'function': 'ale#fixers#reorder_python_imports#Fix',
+\       'suggested_filetypes': ['python'],
+\       'description': 'Sort Python imports with reorder-python-imports.',
+\   },
 \}
 
 " Reset the function registry to the default entries.

autoload/ale/fixers/reorder_python_imports.vim

@@ -0,0 +1,25 @@
+" Author: jake <me@jake.computer>
+" Description: Fixing Python imports with reorder-python-imports.
+
+call ale#Set('python_reorder_python_imports_executable', 'reorder-python-imports')
+call ale#Set('python_reorder_python_imports_options', '')
+call ale#Set('python_reorder_python_imports_use_global', get(g:, 'ale_use_global_executables', 0))
+
+function! ale#fixers#reorder_python_imports#Fix(buffer) abort
+    let l:executable = ale#python#FindExecutable(
+    \   a:buffer,
+    \   'python_reorder_python_imports',
+    \   ['reorder-python-imports'],
+    \)
+
+    if !executable(l:executable)
+        return 0
+    endif
+
+    let l:options = ale#Var(a:buffer, 'python_reorder_python_imports_options')
+
+    return {
+    \   'command': ale#Escape(l:executable)
+    \       . (!empty(l:options) ? ' ' . l:options : '') . ' -',
+    \}
+endfunction