fix(builtins/formatting/black): set the cwd according to the config files (#1603)

* fix(builtins/formatting/black): set the cwd according to the config files

* fixup! fix(builtins/formatting/black): set the cwd according to the config files

Author: Nelyah

lua/null-ls/builtins/formatting/black.lua

@@ -1,4 +1,5 @@
 local h = require("null-ls.helpers")
+local u = require("null-ls.utils")
 local methods = require("null-ls.methods")
 
 local FORMATTING = methods.internal.FORMATTING
@@ -20,6 +21,12 @@ return h.make_builtin({
             "-",
         },
         to_stdin = true,
+        cwd = h.cache.by_bufnr(function(params)
+            return u.root_pattern(
+                -- https://black.readthedocs.io/en/stable/usage_and_configuration/the_basics.html#configuration-via-a-file
+                "pyproject.toml"
+            )(params.bufname)
+        end),
     },
     factory = h.formatter_factory,
 })