add VGenericExpression to ast.md

Author: ota-meshi

Diff for: docs/ast.md

@@ -111,6 +111,11 @@ interface VSlotScopeExpression <: Expression {
     params: [ Pattern | RestElement ]
 }
 
+interface VGenericExpression <: Expression {
+    type: "VGenericExpression"
+    params: [ TSTypeParameter ]
+}
+
 interface VFilterSequenceExpression <: Expression {
     type: "VFilterSequenceExpression"
     expression: Expression
@@ -132,6 +137,7 @@ interface VFilter <: Node {
 - `VForExpression` is an expression node like [ForInStatement] but it has an array as `left` property and does not have `body` property. This is the value of [`v-for` directives].
 - `VOnExpression` is an expression node like [BlockStatement] but it does not have braces. This is the value of [`v-on` directives] only if the `v-on` directive doesn't have that argument.
 - `VSlotScopeExpression` is an expression node like [VariableDeclarator]. This is the value of [`v-slot` directives], [`slot-scope` attributes], and `scope` attributes.
+- `VGenericExpression` is an expression node like typescript-eslint's TSTypeParameterDeclaration. This is the value of [the `generic` attributes on the `<script>` tag](https://vuejs.org/api/sfc-script-setup.html#generics).
 - `VFilterSequenceExpression` is an expression node for [Vue.js Filters](https://vuejs.org/v2/guide/filters.html) syntax.
 
 > Note: `vue-eslint-parser` transforms `v-for="(x, i) in list"` to `for(let [x, i] in list);` then gives the configured parser (`espree` by default) it. This implies that it needs the capability to parse ES2015 destructuring in order to parse [`v-for` directives].