Add some comment on use of new properies to `editorConfig` description.

Add `fontFamily`, `fontSize` and `lineHeight` configuration options to
editors used in notebook cells.

packages/fileeditor-extension/schema/plugin.json

@@ -46,7 +46,7 @@
   "properties": {
     "editorConfig": {
       "title": "Editor Configuration",
-      "description": "The configuration for all text editors.",
+      "description": "The configuration for all text editors.\nIf `fontFamily`, `fontSize` or `lineHeight` are `null`, values from\ncurrent theme are used.",
       "$ref": "#/definitions/editorConfig",
       "default": {
         "autoClosingBrackets": true,

packages/notebook-extension/schema/tracker.json

@@ -9,6 +9,17 @@
         "autoClosingBrackets": {
           "type": "boolean"
         },
+        "fontFamily": {
+          "type": ["string", "null"]
+        },
+        "fontSize": {
+          "type": ["integer", "null"],
+          "minimum": 1,
+          "maximum": 100
+        },
+        "lineHeight": {
+          "type": ["number", "null"]
+        },
         "lineNumbers": {
           "type": "boolean"
         },
@@ -39,6 +50,9 @@
       "$ref": "#/definitions/editorConfig",
       "default": {
         "autoClosingBrackets": true,
+        "fontFamily": null,
+        "fontSize": null,
+        "lineHeight": null,
         "lineNumbers": false,
         "lineWrap": false,
         "matchBrackets": true,
@@ -53,6 +67,9 @@
       "$ref": "#/definitions/editorConfig",
       "default": {
         "autoClosingBrackets": false,
+        "fontFamily": null,
+        "fontSize": null,
+        "lineHeight": null,
         "lineNumbers": false,
         "lineWrap": true,
         "matchBrackets": false,
@@ -67,6 +84,9 @@
       "$ref": "#/definitions/editorConfig",
       "default": {
         "autoClosingBrackets": false,
+        "fontFamily": null,
+        "fontSize": null,
+        "lineHeight": null,
         "lineNumbers": false,
         "lineWrap": true,
         "matchBrackets": false,