Minor wording fixes for custom widget

Author: jtpio

docs/source/examples/Widget Custom.ipynb

@@ -30,7 +30,7 @@
     "\n",
     "To create a custom widget, you need to define the widget both in the browser and in the Python kernel.\n",
     "\n",
-    "This tutorial shows how to build a simple email widget using the TypeScript widget cookiecutter"
+    "This tutorial shows how to build a simple email widget using the TypeScript widget cookiecutter: https://github.com/jupyter-widgets/widget-ts-cookiecutter"
    ]
   },
   {
@@ -50,7 +50,7 @@
     "Next create a conda environment that includes:\n",
     "\n",
     "1. the latest release of JupyterLab or the classic notebook\n",
-    "2. [cookiecutter](https://github.com/cookiecutter/cookiecutter), the tool you will use to bootstrap the custom widget\n",
+    "2. [cookiecutter](https://github.com/cookiecutter/cookiecutter): the tool you will use to bootstrap the custom widget\n",
     "3. [NodeJS](https://nodejs.org): the JavaScript runtime you'll use to\n",
     "   compile the web assets (e.g., TypeScript, CSS) for the custom widget\n",
     "\n",
@@ -85,7 +85,7 @@
     "cookiecutter https://github.com/jupyter-widgets/widget-ts-cookiecutter\n",
     "```\n",
     "\n",
-    "When prompted, enter the desired values like the following for all of the cookiecutter prompts:\n",
+    "When prompted, enter the desired values as follows:\n",
     "\n",
     "```bash\n",
     "author_name []: Your Name\n",
@@ -98,14 +98,14 @@
     "project_short_description [A Custom Jupyter Widget Library]: An Custom Email Widget\n",
     "```\n",
     "\n",
-    "Change to the directory the cookiecutter created and list the files.\n",
+    "Change to the directory the cookiecutter created and list the files:\n",
     "\n",
     "```bash\n",
     "cd ipyemail\n",
     "ls\n",
     "```\n",
     "\n",
-    "You should see a list like the following.\n",
+    "You should see a list like the following:\n",
     "\n",
     "```bash\n",
     "appveyor.yml  css   examples  ipyemail.json  MANIFEST.in   pytest.ini  readthedocs.yml  setup.cfg  src    tsconfig.json\n",
@@ -127,7 +127,7 @@
     "If you are using JupyterLab:\n",
     "\n",
     "```bash\n",
-    "# install the widget manager to display Widgets in the JupyterLab interface\n",
+    "# install the widget manager to display the widgets in JupyterLab\n",
     "jupyter labextension install @jupyter-widgets/jupyterlab-manager --no-build\n",
     "\n",
     "# install the local extension\n",
@@ -161,7 +161,7 @@
     "\n",
     "![hello-world](./images/custom-widget-hello.png)\n",
     "\n",
-    "The next step will walk you through how to modify the existing code to transform the widget into an email widget."
+    "The next steps will walk you through how to modify the existing code to transform the widget into an email widget."
    ]
   },
   {
@@ -225,8 +225,9 @@
     "\n",
     "Instead, you must tell it yourself by defining specially named trait attributes, `_view_name`, `_view_module`, and `_view_module_version` (as seen below) and optionally `_model_name` and `_model_module`.\n",
     "\n",
+    "First let's rename `ipyemail/example.py` to `ipyemail/widget.py`.\n",
     "\n",
-    "In `ipyemail/example.py`, replace the example code with the following:\n",
+    "In `ipyemail/widget.py`, replace the example code with the following:\n",
     "\n",
     "```python\n",
     "from ipywidgets import DOMWidget, ValueWidget, register\n",
@@ -254,13 +255,13 @@
     "In `ipyemail/__init__.py`, change the import from:\n",
     "\n",
     "```python\n",
-    "from .example import ExampleWidget\n",
+    "from .widget import ExampleWidget\n",
     "```\n",
     "\n",
     "To:\n",
     "\n",
     "```python\n",
-    "from .example import Email\n",
+    "from .widget import Email\n",
     "```"
    ]
   },
@@ -433,15 +434,15 @@
     "\n",
     "A handle to the widget's default DOM element can be acquired via `this.el`.  The `el` property is the DOM element associated with the view.\n",
     "\n",
-    "In `src/widget.ts`, define the `email_input` attribute:\n",
+    "In `src/widget.ts`, define the `_emailInput` attribute:\n",
     "\n",
     "```typescript\n",
     "export class EmailView extends DOMWidgetView {\n",
     "  private _emailInput: HTMLInputElement;\n",
     "}\n",
     "```\n",
     "\n",
-    "Then, add the following logic for the `render`:\n",
+    "Then, add the following logic for the `render` method:\n",
     "\n",
     "```typescript\n",
     "render: function() { \n",
@@ -503,8 +504,8 @@
     "We want to be able to avoid user to write an invalid email address, so we need a validator using traitlets.\n",
     "\n",
     "```python\n",
-    "from traitlets import Unicode, Bool, validate, TraitError\n",
     "from ipywidgets import DOMWidget, ValueWidget, register\n",
+    "from traitlets import Unicode, Bool, validate, TraitError\n",
     "\n",
     "from ._frontend import module_name, module_version\n",
     "\n",