languagetools: stop auto-appending --autoDetect (#2616)

Options are now configurable for languagetools, and `--autoDetect` can be removed by changing the options.

autoload/ale/handlers/languagetool.vim

@@ -2,6 +2,7 @@
 " Description: languagetool for markdown files
 "
 call ale#Set('languagetool_executable', 'languagetool')
+call ale#Set('languagetool_options', '--autoDetect')
 
 function! ale#handlers#languagetool#GetExecutable(buffer) abort
     return ale#Var(a:buffer, 'languagetool_executable')
@@ -9,8 +10,10 @@ endfunction
 
 function! ale#handlers#languagetool#GetCommand(buffer) abort
     let l:executable = ale#handlers#languagetool#GetExecutable(a:buffer)
+    let l:options = ale#Var(a:buffer, 'languagetool_options')
 
-    return ale#Escape(l:executable) . ' --autoDetect %s'
+    return ale#Escape(l:executable)
+    \ . (empty(l:options) ? '' : ' ' . l:options) . ' %s'
 endfunction
 
 function! ale#handlers#languagetool#HandleOutput(buffer, lines) abort

doc/ale.txt

@@ -1967,6 +1967,14 @@ g:ale_languagetool_executable                   *g:ale_languagetool_executable*
   The executable to run for languagetool.
 
 
+g:ale_languagetool_options                         *g:ale_languagetool_options*
+                                                   *b:ale_languagetool_options*
+  Type: |String|
+  Default: `'--autoDetect'`
+
+  This variable can be set to pass additional options to languagetool.
+
+
 -------------------------------------------------------------------------------
 7.3. Options for write-good                            *ale-write-good-options*
 

test/command_callback/test_languagetool_command_callback.vader

@@ -12,4 +12,11 @@ Execute(Should be able to set a custom executable):
   let g:ale_languagetool_executable = 'foobar'
 
   AssertLinter 'foobar' , ale#Escape('foobar')
-  \   . ' --autoDetect %s'
+  \ . ' --autoDetect %s'
+
+Execute(Should be able to include custom languagetool options):
+  let g:ale_languagetool_options = '--language en'
+
+  " is now 'foobar' based on above global
+  AssertLinter 'foobar', ale#Escape('foobar')
+  \ . ' --language en %s'