Added script API docs

docs/en/en.json

@@ -520,6 +520,10 @@
                         "path": "/manuals/extensions-defold-sdk",
                         "name": "Defold SDK"
                     },
+                    {
+                        "path": "/manuals/extensions-script-api",
+                        "name": "Adding auto-complete definition"
+                    },
                     {
                         "path": "/manuals/extensions-best-practices",
                         "name": "Best Practices"

docs/en/manuals/extensions-script-api.md

@@ -0,0 +1,52 @@
+---
+title: Adding editor auto-complete to a native extensions
+brief: This manual explains how to create a script API definition so that the Defold editor can provide auto-complete for users of an extension.
+---
+
+# Auto-complete for native extensions
+
+The Defold editor will provide auto-complete suggestions for all Defold API functions and it will try to generate suggestions for Lua modules required by your scripts. The editor is however unable to provide auto-complete suggestions for the functionality exposed by native extensions. In the case of native extensions it is up to the extension author to generate a script API definition file that the editor can use to provide auto-complete suggestions.
+
+
+## Creating a script API definition
+
+A script API definition file has the extension `.script_api` and it is a file in [YAML format](https://yaml.org/). The expected format for a script API definition is:
+
+```yml
+- name: The name of the extension
+  type: table
+  desc: Extension description
+  members:
+  - name: Name of the first member
+    type: Member type
+    desc: Member description
+    # if member type is "function"
+    parameters:
+    - name: Name of the first parameter
+      type: Parameter type
+      desc: Parameter description
+    - name: Name of the second parameter
+      type: Parameter type
+      desc: Parameter description
+    # if member type is "function"
+    returns:
+    - name: Name of first return value
+      type: Return value type
+      desc: Return value description
+    examples:
+    - desc: First example of member usage
+    - desc: Second example of member usage
+
+  - name: Name of the second member
+    ...
+```
+
+Types can be any of `table, string , boolean, number, function`. If a value can have multiple types it is written as `[type1, type2, type3]`.
+
+
+## Examples
+
+Refer to the following projects for actual usage examples:
+
+* [Facebook extension](https://github.com/defold/extension-facebook/tree/master/facebook/api)
+* [WebView extension](https://github.com/defold/extension-webview/blob/master/webview/api/webview.script_api)