Add support for Black's preview style

https://black.readthedocs.io/en/stable/the_black_code_style/future_style.html#preview-style

Author: flother

Scripts/BlackProcess.js

@@ -11,10 +11,16 @@ class BlackProcess {
     const maxLineLength =
       nova.workspace.config.get("is.flother.Blake.maxLineLength") ??
       nova.config.get("is.flother.Blake.maxLineLength");
+    const previewStyle =
+      nova.workspace.config.get("is.flother.Blake.blackPreviewStyle") ||
+      nova.config.get("is.flother.Blake.blackPreviewStyle");
     let commandArguments = ["--quiet", "-"];
     if (maxLineLength) {
       commandArguments = ["--line-length", maxLineLength.toString(), ...commandArguments];
     }
+    if (previewStyle) {
+      commandArguments = ["--preview", ...commandArguments];
+    }
     if (!blackPath) {
       blackPath = "/usr/bin/env";
       commandArguments = ["black", ...commandArguments];

config.json

@@ -41,6 +41,14 @@
         "title": "Format Python source code files on save",
         "type": "boolean",
         "default": false
+      },
+      {
+        "key": "is.flother.Blake.blackPreviewStyle",
+        "title": "Enable preview style",
+        "description": "Include experimental style changes",
+        "link": "https://black.readthedocs.io/en/stable/the_black_code_style/future_style.html#preview-style",
+        "type": "boolean",
+        "default": false
       }
     ]
   }