Go: Add gotype support (#1099)

ale_linters/go/gotype.vim

@@ -0,0 +1,23 @@
+" Author: Jelte Fennema <github-public@jeltef.nl>
+" Description: gotype for Go files
+
+call ale#linter#Define('go', {
+\   'name': 'gotype',
+\   'output_stream': 'stderr',
+\   'executable': 'gotype',
+\   'command_callback': 'ale_linters#go#gotype#GetCommand',
+\   'callback': 'ale#handlers#unix#HandleAsError',
+\})
+
+"\   'command':
+function! ale_linters#go#gotype#GetCommand(buffer) abort
+    let l:cur_file = expand('#' . a:buffer . ':p')
+    if l:cur_file =~# '_test\.go$'
+        return
+    endif
+
+    let l:module_files = globpath(expand('#' . a:buffer . ':p:h'), '*.go', 0, 1)
+    let l:other_module_files = filter(l:module_files, 'v:val isnot# ' . ale#util#EscapeVim(l:cur_file) . ' && v:val !~# "_test\.go$"')
+    return 'gotype %t ' . join(map(l:other_module_files, 'ale#Escape(v:val)'))
+
+endfunction