Clarify blockquote render hook Markdown syntax

content/en/render-hooks/blockquotes.md

@@ -28,15 +28,13 @@ Blockquote render hook templates receive the following [context]:
 
 {{< new-in 0.134.0 >}}
 
-(`hstring.HTML`) Applicable when [`Type`](#type) is `alert` when using [Obsidian callouts] syntax, this is the alert title converted to HTML. 
+(`template.HTML`) Applicable when [`Type`](#type) is `alert`, this is the alert title. See the [alerts](#alerts) section below.
 
 ###### AlertSign
 
 {{< new-in 0.134.0 >}}
 
-(`string`) Applicable when [`Type`](#type) is `alert` when using [Obsidian callouts] syntax, this is one of "+", "-" or "" (empty string) to indicate the presence of a foldable sign.
-
-[Obsidian callouts]: https://help.obsidian.md/Editing+and+formatting/Callouts
+(`string`) Applicable when [`Type`](#type) is `alert`, this is the alert sign. Typically used to indicate whether an alert is graphically foldable, this is one of&nbsp;`+`,&nbsp;`-`,&nbsp;or an empty string. See the [alerts](#alerts) section below.
 
 ###### Attributes
 
@@ -110,7 +108,11 @@ Then in your markdown:
 
 ## Alerts
 
-Also known as _callouts_ or _admonitions_, alerts are blockquotes used to emphasize critical information. For example:
+Also known as _callouts_ or _admonitions_, alerts are blockquotes used to emphasize critical information.
+
+### Basic syntax
+
+With the basic Markdown syntax, the first line of each alert is an alert designator consisting of an exclamation point followed by the alert type, wrapped within brackets. For example:
 
 {{< code file=content/example.md lang=text >}}
 > [!NOTE]
@@ -129,14 +131,30 @@ Also known as _callouts_ or _admonitions_, alerts are blockquotes used to emphas
 > Advises about risks or negative outcomes of certain actions.
 {{< /code >}}
 
+The basic syntax is compatible with [GitHub], [Obsidian], and [Typora].
+
+[GitHub]: https://docs.github.com/en/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax#alerts
+[Obsidian]: https://help.obsidian.md/Editing+and+formatting/Callouts
+[Typora]: https://support.typora.io/Markdown-Reference/#callouts--github-style-alerts
+
+### Extended syntax
+
+With the extended Markdown syntax, you may optionally include an alert sign and/or an alert title. The alert sign is one of&nbsp;`+`&nbsp;or&nbsp;`-`, typically used to indicate whether an alert is graphically foldable. For example:
+
+{{< code file=content/example.md lang=text >}}
+> [!WARNING]+ Radiation hazard
+> Do not approach or handle without protective gear.
+{{< /code >}}
+
+The extended syntax is compatible with [Obsidian].
+
 {{% note %}}
-This syntax is compatible with both the GitHub Alert Markdown extension and Obsidian's callout syntax. 
-But note that GitHub will not recognize callouts with one of Obsidian's extensions (e.g. callout title or the foldable sign).
+The extended syntax is not compatible with GitHub or Typora. If you include an alert sign or an alert title, these applications render the Markdown as a blockquote.
 {{% /note %}}
 
-The first line of each alert is an alert designator consisting of an exclamation point followed by the alert type, wrapped within brackets.
+### Example
 
-The blockquote render hook below renders a multilingual alert if an alert designator is present, otherwise it renders a blockquote according to the CommonMark specification.
+This blockquote render hook renders a multilingual alert if an alert designator is present, otherwise it renders a blockquote according to the CommonMark specification.
 
 {{< code file=layouts/_default/_markup/render-blockquote.html copy=true >}}
 {{ $emojis := dict
@@ -151,7 +169,11 @@ The blockquote render hook below renders a multilingual alert if an alert design
   <blockquote class="alert alert-{{ .AlertType }}">
     <p class="alert-heading">
       {{ transform.Emojify (index $emojis .AlertType) }}
-      {{ or (i18n .AlertType) (title .AlertType) }}
+      {{ with .AlertTitle }}
+        {{ . }}
+      {{ else }}
+        {{ or (i18n .AlertType) (title .AlertType) }}
+      {{ end }}
     </p>
     {{ .Text }}
   </blockquote>
@@ -172,7 +194,6 @@ tip = 'Tip'
 warning = 'Warning'
 {{< /code-toggle >}}
 
-
 Although you can use one template with conditional logic as shown above, you can also create separate templates for each [`Type`](#type) of blockquote:
 
 ```text