Allow all Python linter executables to be set to pipenv.

It appends ` run {linter_name}`, analogously to the Ruby linters when
the executable is set to `bundle`

ale_linters/python/mypy.vim

@@ -23,10 +23,14 @@ function! ale_linters#python#mypy#GetCommand(buffer) abort
     let l:dir = s:GetDir(a:buffer)
     let l:executable = ale_linters#python#mypy#GetExecutable(a:buffer)
 
+    let l:exec_args = l:executable =~? 'pipenv$'
+    \   ? ' run mypy'
+    \   : ''
+
     " We have to always switch to an explicit directory for a command so
     " we can know with certainty the base path for the 'filename' keys below.
     return ale#path#CdString(l:dir)
-    \   . ale#Escape(l:executable)
+    \   . ale#Escape(l:executable) . l:exec_args
     \   . ' --show-column-numbers '
     \   . ale#Var(a:buffer, 'python_mypy_options')
     \   . ' --shadow-file %s %t %s'

ale_linters/python/prospector.vim

@@ -14,7 +14,14 @@ function! ale_linters#python#prospector#GetExecutable(buffer) abort
 endfunction
 
 function! ale_linters#python#prospector#GetCommand(buffer) abort
-    return ale#Escape(ale_linters#python#prospector#GetExecutable(a:buffer))
+    let l:executable = ale_linters#python#prospector#GetExecutable(a:buffer)
+
+    let l:exec_args = l:executable =~? 'pipenv$'
+    \   ? ' run prospector'
+    \   : ''
+
+    return ale#Escape(l:executable)
+    \   . l:exec_args
     \   . ' ' . ale#Var(a:buffer, 'python_prospector_options')
     \   . ' --messages-only --absolute-paths --zero-exit --output-format json'
     \   . ' %s'

ale_linters/python/pycodestyle.vim

@@ -10,7 +10,13 @@ function! ale_linters#python#pycodestyle#GetExecutable(buffer) abort
 endfunction
 
 function! ale_linters#python#pycodestyle#GetCommand(buffer) abort
-    return ale#Escape(ale_linters#python#pycodestyle#GetExecutable(a:buffer))
+    let l:executable = ale_linters#python#pycodestyle#GetExecutable(a:buffer)
+
+    let l:exec_args = l:executable =~? 'pipenv$'
+    \   ? ' run pycodestyle'
+    \   : ''
+
+    return ale#Escape(l:executable) . l:exec_args
     \   . ' '
     \   . ale#Var(a:buffer, 'python_pycodestyle_options')
     \   . ' -'

ale_linters/python/pyflakes.vim

@@ -11,7 +11,13 @@ endfunction
 function! ale_linters#python#pyflakes#GetCommand(buffer) abort
     let l:executable = ale_linters#python#pyflakes#GetExecutable(a:buffer)
 
-    return ale#Escape(l:executable) . ' %t'
+    let l:exec_args = l:executable =~? 'pipenv$'
+    \   ? ' run pyflakes'
+    \   : ''
+
+    return ale#Escape(l:executable)
+    \   . l:exec_args
+    \   . ' %t'
 endfunction
 
 function! ale_linters#python#pyflakes#Handle(buffer, lines) abort

ale_linters/python/pylint.vim

@@ -15,8 +15,14 @@ function! ale_linters#python#pylint#GetCommand(buffer) abort
     \   ? ale#path#BufferCdString(a:buffer)
     \   : ''
 
+    let l:executable = ale_linters#python#pylint#GetExecutable(a:buffer)
+
+    let l:exec_args = l:executable =~? 'pipenv$'
+    \   ? ' run pylint'
+    \   : ''
+
     return l:cd_string
-    \   . ale#Escape(ale_linters#python#pylint#GetExecutable(a:buffer))
+    \   . ale#Escape(l:executable) . l:exec_args
     \   . ' ' . ale#Var(a:buffer, 'python_pylint_options')
     \   . ' --output-format text --msg-template="{path}:{line}:{column}: {msg_id} ({symbol}) {msg}" --reports n'
     \   . ' %s'

ale_linters/python/pyls.vim

@@ -11,7 +11,11 @@ endfunction
 function! ale_linters#python#pyls#GetCommand(buffer) abort
     let l:executable = ale_linters#python#pyls#GetExecutable(a:buffer)
 
-    return ale#Escape(l:executable)
+    let l:exec_args = l:executable =~? 'pipenv$'
+    \   ? ' run pyls'
+    \   : ''
+
+    return ale#Escape(l:executable) . l:exec_args
 endfunction
 
 call ale#linter#Define('python', {