Added new MkDocs 1.5 settings to JSON schema

* added support for two new entries in mkdocs.yml

`exclude_docs` and `not_in_nav` were introduced in MkDocs Version 1.5

* added support for the validation field

* using $defs, supporting simplified form, no additional props

- this should support the forms of definitions described in the manual
  https://www.mkdocs.org/user-guide/configuration/#validation
  including uses with `nav` and `link` sections as well as without
- making use of a `$defs` section to avoid too much duplication
- added `"additionalProperties": false`

* moved `additionalProperties` for consistency with style

docs/schema.json

@@ -154,6 +154,19 @@
     "nav": {
       "$ref": "schema/nav.json"
     },
+    "validation": {
+      "$ref": "schema/validation.json"
+    },
+    "exclude_docs": {
+      "title": "Pattern to declare files to exclude from build",
+      "markdownDescription": "https://www.mkdocs.org/user-guide/configuration/#exclude_docs",
+      "type": "string"
+    },
+    "not_in_nav": {
+      "title": "Pattern to declare pages that do not appear in the navigation",
+      "markdownDescription": "https://www.mkdocs.org/user-guide/configuration/#not_in_nav",
+      "type": "string"
+    },
     "watch": {
       "items": {
         "title": "Path to watch for changes",

docs/schema/validation.json

@@ -0,0 +1,53 @@
+{
+  "$schema": "https://json-schema.org/draft-07/schema",
+  "title": "Validation settings",
+  "markdownDescription": "https://www.mkdocs.org/user-guide/configuration/#validation",
+  "type": "object",
+  "properties": {
+    "omitted_files": { "$ref": "#/$defs/omitted_files" },
+    "not_found": { "$ref": "#/$defs/not_found" },
+    "absolute_links": { "$ref": "#/$defs/absolute_links" },
+    "nav": {
+      "title": "validation of navigation",
+      "markdownDescription": "https://www.mkdocs.org/user-guide/configuration/#validation",
+      "properties": {
+        "omitted_files": { "$ref": "#/$defs/omitted_files" },
+        "not_found": { "$ref": "#/$defs/not_found" },
+        "absolute_links": { "$ref": "#/$defs/absolute_links" }
+      },
+      "additionalProperties": false
+    },
+    "links": {
+      "title": "Validation of links",
+      "markdownDescription": "https://www.mkdocs.org/user-guide/configuration/#validation",
+      "properties": {
+        "not_found": { "$ref": "#/$defs/not_found" },
+        "absolute_links": { "$ref": "#/$defs/absolute_links" },
+        "unrecognized_links": { "$ref": "#/$defs/unrecognized_links" }
+      },
+      "additionalProperties": false
+    }
+  },
+  "additionalProperties": false,
+  "$defs": {
+    "omitted_files": {
+      "title": "warning level when files exist but are not referenced in navigation",
+      "$ref": "#/$defs/warning_levels"
+    },
+    "not_found": {
+      "title": "warning level when file referenced is not found or is excluded",
+      "$ref": "#/$defs/warning_levels"
+    },
+    "absolute_links": {
+      "title": "warning level when absolute links are used",
+      "$ref": "#/$defs/warning_levels"
+    },
+    "unrecognized_links": {
+      "title": "warning level when a relative link cannot be resolved to a document",
+      "$ref": "#/$defs/warning_levels"
+    },
+    "warning_levels": {
+      "enum": ["warn", "info", "ignore"]
+    }
+  }
+}