chore: add missing anchors (#2172)

Author: jay-es

src/api/general.md

@@ -122,7 +122,7 @@ A type helper for defining a Vue component with type inference.
   type FooInstance = InstanceType<typeof Foo>
   ```
 
-  ### Note on webpack Treeshaking
+  ### Note on webpack Treeshaking {#note-on-webpack-treeshaking}
 
   Because `defineComponent()` is a function call, it could look like that it would produce side-effects to some build tools, e.g. webpack. This will prevent the component from being tree-shaken even when the component is never used.
 

src/ecosystem/newsletters.md

@@ -1,4 +1,4 @@
-# Community Newsletters
+# Community Newsletters {#community-newsletters}
 
 There are many great newsletters / Vue-dedicated blogs from the community bringing you latest news and happenings in the Vue ecosystem. Here is a non-exhaustive list of active ones that we have come across:
 

src/guide/components/v-model.md

@@ -1,4 +1,4 @@
-# Component v-model
+# Component v-model {#component-v-model}
 
 `v-model` can be used on a component to implement a two-way binding.
 

src/guide/reusability/plugins.md

@@ -1,4 +1,4 @@
-# Plugins
+# Plugins {#plugins}
 
 ## Introduction {#introduction}
 

src/guide/typescript/composition-api.md

@@ -131,7 +131,7 @@ export default defineComponent({
 })
 ```
 
-### Complex prop types
+### Complex prop types {#complex-prop-types}
 
 With type-based declaration, a prop can use a complex type much like any other type: