Add documentation for using Milkdown with various frameworks

- Created a new document for using components in Milkdown.
- Added a guide for using plugins in Milkdown, including toggling plugins programmatically and listing official plugins.
- Introduced a recipe for integrating Milkdown with Angular, including installation steps and component creation.
- Added a recipe for using Milkdown with Next.js, detailing installation and component setup.
- Created a guide for integrating Milkdown with NuxtJS, including installation and component creation.
- Added a comprehensive guide for using Milkdown with React, covering both Crepe and core Milkdown usage.
- Introduced a recipe for SolidJS integration with Milkdown, including installation and component creation.
- Added a guide for using Milkdown with Svelte, detailing installation and component setup.
- Created a comprehensive guide for integrating Milkdown with Vue, covering both Crepe and core Milkdown usage.
- Added a recipe for using Milkdown with Vue2, including installation and component creation.

milkdown-docs/plugin/composable-plugins.md

@@ -0,0 +1,85 @@
+# Composable Plugins
+
+In the previous section, we showed you how to create a plugin from scratch. Luckily, you don't need to do that in most cases. Milkdown provides a lot of helpers in [@milkdown/utils](/docs/api/utils) to make it easier to create plugins. The **composable** here means that you can use the plugin in other plugins. For example, you can use a command plugin in a keymap plugin. This is a very common pattern in Milkdown.
+
+I'll show you some examples of how to use composable plugins. But I won't go into detail about the options and the usage of each plugin. You can find the details in the [API reference](/docs/api/utils#composable).
+
+## Schema
+
+The schema plugin is the most important plugin in Milkdown. It defines the structure of the document. A schema plugin in milkdown is a super set of the [node schema spec](https://prosemirror.net/docs/ref/#model.NodeSpec) or [mark schema spec](https://prosemirror.net/docs/ref/#model.MarkSpec) in ProseMirror.
+
+Let's create a simple blockquote node plugin as an example:
+
+```typescript
+import { $node } from "@milkdown/kit/utils";
+
+const blockquote = $node("blockquote", () => ({
+  content: "block+",
+  group: "block",
+  defining: true,
+  parseDOM: [{ tag: "blockquote" }],
+  toDOM: (node) => ["blockquote", ctx.get(blockquoteAttr.key)(node), 0],
+  parseMarkdown: {
+    match: ({ type }) => type === "blockquote",
+    runner: (state, node, type) => {
+      state.openNode(type).next(node.children).closeNode();
+    },
+  },
+  toMarkdown: {
+    match: (node) => node.type.name === "blockquote",
+    runner: (state, node) => {
+      state.openNode("blockquote").next(node.content).closeNode();
+    },
+  },
+}));
+```
+
+## Input Rule
+
+Since we have a blockquote node, we can create an input rule plugin to make it easier to create a blockquote node.
+We expect that when we type `> ` at the beginning of a line, the blockquote node will be created.
+
+```typescript
+import { wrappingInputRule } from "@milkdown/kit/prose/inputrules";
+import { $inputRule } from "@milkdown/kit/utils";
+
+export const wrapInBlockquoteInputRule = $inputRule(() =>
+  wrappingInputRule(/^\s*>\s$/, blockquoteSchema.type()),
+);
+```
+
+## Command
+
+We can also create a command plugin to create a blockquote node.
+The command is useful when we want to create a button to create a blockquote node.
+
+```typescript
+import { wrapIn } from "@milkdown/kit/prose/commands";
+import { $command } from "@milkdown/kit/utils";
+
+export const wrapInBlockquoteCommand = $command(
+  "WrapInBlockquote",
+  () => () => wrapIn(blockquoteSchema.type()),
+);
+```
+
+## Shortcut
+
+We can also create a shortcut plugin for blockquote.
+Here we use `Ctrl + Shift + B` as the shortcut. When we press this shortcut, the blockquote node will be created.
+And we can also use the command we created in the previous section.
+
+```typescript
+import { commandsCtx } from "@milkdown/kit/core";
+import { $useKeymap } from "@milkdown/kit/utils";
+
+export const blockquoteKeymap = $useKeymap("blockquoteKeymap", {
+  WrapInBlockquote: {
+    shortcuts: "Mod-Shift-b",
+    command: (ctx) => {
+      const commands = ctx.get(commandsCtx);
+      return () => commands.call(wrapInBlockquoteCommand.key);
+    },
+  },
+});
+```