Add phone-call-link use case (#733)

* add phone-call-link page

* add reference info widgets to phone call use case

Author: alex-cit

src/.vitepress/sidebar/en.js

@@ -90,9 +90,10 @@ export default {
         { text: 'Use Cases', link: '/layer/use-cases/', 
         collapsed: true,
         items: [
-	       { text: 'How to Open a File', link: '/layer/open-file/' },
-	       { text: 'How to Use Hyperlinks', link: '/layer/external-link/' },
+	   { text: 'How to Open a File', link: '/layer/open-file/' },
+	   { text: 'How to Use Hyperlinks', link: '/layer/external-link/' },
            { text: 'How to Open a Link to a Navigation App', link: '/layer/link-to-navigation/' },
+           { text: 'How to Use a Phone Call Link', link: '/layer/phone-call-link/' },
            { text: 'How to Link Multiple Records to One Feature (1-N Relations)', link: '/layer/one-to-n-relations/' },
            { text: 'How to Embed an Image', link: '/layer/embed-image/' },
         ] },

src/index.md

@@ -91,6 +91,7 @@ The ecosystem consist of various components:
    - [How to Open a File ](./layer/open-file/)
    - [How to Use Hyperlinks](./layer/external-link/)
    - [How to Open a Link to a Navigation App](./layer/link-to-navigation/)
+   - [How to Use a Phone Call Link ](./layer/phone-call-link/)
    - [How to Link Multiple Records to One Feature](./layer/one-to-n-relations/)
    - [How to Embed an Image](./layer/embed-image/)
 

src/layer/info-widgets/index.md

@@ -7,7 +7,7 @@ description: HTML and Text widgets are not connected to a specific field of the
 
 <QGISHelp ver="latest" link="/user_manual/working_with_vector/vector_properties.html#other-widgets" text="QGIS" /> also offers widgets that can be added to the form to display values or text, but are not connected to a specific field of the layer, such as the Text or HTML widget. These widgets are also supported by <MainPlatformName />. 
 
-HTML and Text widgets can be used, e.g., to display instructions in the form. They can include [expressions and field values](#using-expressions-in-text-and-html-widgets) as well. The HTML widget supports various [HTML tags](https://doc.qt.io/qt-6/richtext-html-subset.html#supported-tags), so it can also be used, for instance, to display [online images](../embed-image/) or [open local files](../open-file/).
+HTML and Text widgets can be used, e.g., to display instructions in the form. They can include [expressions and field values](#using-expressions-in-text-and-html-widgets) as well. The HTML widget supports various [HTML tags](https://doc.qt.io/qt-6/richtext-html-subset.html#supported-tags), so it can also be used, for instance, to display [online images](../embed-image/), [phone call link](../phone-call-link/) or [open local files](../open-file/).
 
 |<div style="width:150px"> Widget </div> |Preview in the <MobileAppNameShort />|
 |:---:|:---:|

src/layer/link-to-navigation/index.md

@@ -7,7 +7,7 @@ description: Hyperlinks can be used in the attributes form in Mergin Maps mobile
 
 Attributes forms can include clickable links that can be used to open a navigation app directly from the form in <MobileAppName />.  
 
-:::tip
+:::tip Example project available
 Clone <MerginMapsProject id="documentation/forms-navigation-link" /> to follow this example!
 :::
 

src/layer/phone-call-link/index.md

@@ -0,0 +1,23 @@
+---
+description: HTML widget can be used to initiate a phone call directly from the feature's form in Mergin Maps mobile app.
+---
+
+# How to Use a Phone Call Link
+
+The HTML widget can be used to display a link that will trigger a phone call directly from the form in <MobileAppName />.
+
+:::tip Example project available
+Clone <MerginMapsProject id="documentation/phone-call-link" /> to see how this works.
+:::
+
+Add the [HTML widget](../info-widgets/) to the **Attributes form** of your survey layer. Use the following configuration (replace `123-456-789` by the phone number you want to use):
+```
+<a href="tel:123-456-789">123-456-789</a>
+```
+
+![QGIS Attributes form HTML widget with phone call link](./qgis-form-html-phone-call.webp "QGIS Attributes form HTML widget with phone call link")
+
+In the <MobileAppNameShort />, the form now contains a link that can initiate a phone call.
+![Mergin Maps mobile app form with phone call link](./mobile-form-html-phone-call.webp "Mergin Maps mobile app form with phone call link")
+
+