Add Formatting Text Walkthrough section

Author: rojvv

src/formatting-text.md

@@ -0,0 +1,74 @@
+---
+title: Formatting Text
+parent: /#walkthrough
+prev: /inline-queries
+---
+
+Messages and media captions can contain formatting such as bold text, links, spoilers, and code. MTKruto can parse HTML or Markdown into Telegram message entities.
+
+## HTML
+
+Set `parseMode` to `"HTML"` for a message that contains supported HTML tags.
+
+```ts
+await client.sendMessage(
+  chatId,
+  'Hello, <b>world</b>! Visit <a href="https://mtkru.to">MTKruto</a>.',
+  { parseMode: "HTML" },
+);
+```
+
+Common supported tags include `<b>`, `<i>`, `<u>`, `<s>`, `<code>`, `<pre>`, `<blockquote>`, and `<a>`.
+
+## Markdown
+
+Set `parseMode` to `"Markdown"` to use Markdown formatting.
+
+```ts
+await ctx.reply(
+  "Hello, *world*\\! Visit [MTKruto](https://mtkru.to)\\.",
+  { parseMode: "Markdown" },
+);
+```
+
+Characters with special meaning must be escaped when they should appear literally. Be especially careful when inserting user-provided text into HTML or Markdown.
+
+## Default Parse Mode
+
+A default parse mode can be configured when constructing the client. It is then used whenever a method does not specify one.
+
+```ts
+const client = new Client({
+  parseMode: "HTML",
+  /* ... */
+});
+```
+
+Override the default for a single message by passing another parse mode, or pass `null` to disable parsing.
+
+```ts
+await client.sendMessage(chatId, "<b>This remains unchanged.</b>", {
+  parseMode: null,
+});
+```
+
+## Explicit Entities
+
+You can provide {{ "MessageEntity" |> t }} objects instead of using markup. Entity offsets and lengths use UTF-16 code units, which is how JavaScript measures string length.
+
+```ts
+const text = "Important message";
+
+await client.sendMessage(chatId, text, {
+  parseMode: null,
+  entities: [
+    {
+      type: "bold",
+      offset: 0,
+      length: "Important".length,
+    },
+  ],
+});
+```
+
+Explicit entities are useful when text is assembled dynamically because formatting does not depend on escaping markup characters.

src/index.md

@@ -34,6 +34,7 @@ Its key features include:
 9. [Keyboards and Callback Queries](/keyboards-and-callback-queries) {{ "/keyboards-and-callback-queries" |> i }}
 10. [Files](/files) {{ "/files" |> i }}
 11. [Inline Queries](/inline-queries) {{ "/inline-queries" |> i }}
+12. [Formatting Text](/formatting-text) {{ "/formatting-text" |> i }}
 
 ### Guides
 

src/inline-queries.md

@@ -2,6 +2,7 @@
 title: Inline Queries
 parent: /#walkthrough
 prev: /files
+next: /formatting-text
 ---
 
 Inline mode lets users interact with a bot from any chat by typing its username followed by a query. It must first be enabled for the bot through [@BotFather](https://t.me/BotFather).