Move max line length setting to General section

It affects both Black and Flake8 so it makes sense to move it out of the
Black section.

Author: flother

extension.json

@@ -27,6 +27,19 @@
     ]
   },
   "configWorkspace": [
+    {
+      "title": "General",
+      "type": "section",
+      "children": [
+        {
+          "key": "is.flother.Blake.maxLineLength",
+          "title": "Max line length",
+          "description": "Maximum number of characters allowed per line",
+          "type": "number",
+          "placeholder": 88
+        }
+      ]
+    },
     {
       "title": "Flake8",
       "type": "section",
@@ -51,12 +64,6 @@
           "type": "path",
           "placeholder": "/usr/bin/env black"
         },
-        {
-          "key": "is.flother.Blake.maxLineLength",
-          "title": "Max line length",
-          "type": "number",
-          "placeholder": 88
-        },
         {
           "key": "is.flother.Blake.formatOnSave",
           "title": "Format Python source code files on save",