Add documentation for rule

docs/input/widgets/rule.md

@@ -0,0 +1,71 @@
+Title: Rule
+Order: 5
+RedirectFrom: rule
+---
+
+The `Rule` class is used to render a horizontal rule (line) to the terminal.
+
+![Rule](../assets/images/rule.png)
+
+# Usage
+
+To render a rule without a title:
+
+```csharp
+var rule = new Rule();
+AnsiConsole.Render(rule);
+```
+
+## Title
+
+You can set the rule title markup text.
+
+```csharp
+var rule = new Rule("[red]Hello[/]");
+AnsiConsole.Render(rule);
+
+// output
+───────────────────────────────── Hello ─────────────────────────────────
+```
+
+### Title alignment
+
+You can set the rule's title alignment.
+
+```csharp
+var rule = new Rule("[red]Hello[/]");
+rule.Alignment = Justify.Left;
+AnsiConsole.Render(rule);
+
+//output
+── Hello ────────────────────────────────────────────────────────────────
+```
+
+You can also specify it with a method
+
+```csharp
+var rule = new Rule("[red]Hello[/]");
+rule.LeftAligned();
+AnsiConsole.Render(rule);
+
+//output
+── Hello ────────────────────────────────────────────────────────────────
+```
+
+
+## Style
+
+You can set the rule style.
+
+```csharp
+var rule = new Rule("[red]Hello[/]");
+rule.Style = Style.Parse("red dim");
+AnsiConsole.Render(rule);
+```
+You can also specify it with a method
+
+```csharp
+var rule = new Rule("[red]Hello[/]");
+rule.SetStyle("red dim");
+AnsiConsole.Render(rule);
+```