add spectral support for json

ale_linters/json/spectral.vim

@@ -0,0 +1,14 @@
+" Author: t2h5 <https://github.com/t2h5>
+" Description: Integration of Stoplight Spectral CLI with ALE.
+
+call ale#Set('json_spectral_executable', 'spectral')
+call ale#Set('json_spectral_use_global', get(g:, 'ale_use_global_executables', 0))
+
+call ale#linter#Define('json', {
+\   'name': 'spectral',
+\   'executable': {b -> ale#node#FindExecutable(b, 'json_spectral', [
+\       'node_modules/.bin/spectral',
+\   ])},
+\   'command': '%e lint --ignore-unknown-format -q -f text %t',
+\   'callback': 'ale#handlers#spectral#HandleSpectralOutput'
+\})