refactor: address comments

Author: ulivz

Diff for: packages/@vuepress/core/lib/theme-api/index.js

@@ -22,6 +22,7 @@ module.exports = class ThemeAPI {
 
   init () {
     const alias = {
+      '@theme': this.theme.path,
       '@current-theme': this.theme.path
     }
     if (this.existsParentTheme) {

Diff for: packages/docs/docs/miscellaneous/glossary.md

@@ -48,9 +48,9 @@ That is, those titles defined by one or more `#` in `markdown`.
 
 ## themeConfig
 
-- Access: `$site | Context.themeConfig`
+- Access: `$themeConfig | Context.themeConfig`
 
-Value of `themeConfig` in `.vuepress/config.js`, i.e., `user's theme configuration`.
+Value of `themeConfig` in `.vuepress/config.js`, i.e., user's theme configuration.
 
 ## themePath
 
@@ -70,7 +70,7 @@ Theme's configuration file - `themePath/index.js`.
 
 If the current theme is a derived theme, `parentThemePath` refers to the absolute path of the parent theme.
 
-## parentThemeNetry
+## parentThemeEntry
 
 - Access: `Context.themeAPI.parentTheme.entry`
 

Diff for: packages/docs/docs/theme/inheritance.md

@@ -138,7 +138,7 @@ On this premise, when you create a `Navbar` component in the same place in the c
 
 ::: vue
 theme
-└──  components
+└── components
     └── `Navbar.vue`
 ::: 
 

Diff for: packages/docs/docs/zh/miscellaneous/glossary.md

@@ -50,7 +50,7 @@ sidebar: auto
 
 ## themeConfig
 
-- Access: `$site | Context.themeConfig`
+- Access: `$themeConfig | Context.themeConfig`
 
 即 `.vuepress/config.js` 中 `themeConfig` 的值，是用户对当前所使用的主题的配置。
 
@@ -72,7 +72,7 @@ sidebar: auto
 
 如果当前使用的主题是一个派生主题，那么 `parentThemePath` 就是指父主题的所在绝对路径。
 
-## parentThemeNetry
+## parentThemeEntry
 
 - Access: `Context.themeAPI.parentTheme.entry`
 

Diff for: packages/docs/docs/zh/theme/inheritance.md

@@ -137,7 +137,7 @@ import Home from '@theme/components/Navbar.vue'
 
 ::: vue
 theme
-└──  components
+└── components
     └── `Navbar.vue`
 ::: 
 

Diff for: packages/docs/docs/zh/theme/using-a-theme.md

@@ -2,7 +2,7 @@
 
 使用一个主题和使用一个插件的方式几乎一致。
 
-## 使用来自依赖的插件
+## 使用来自依赖的主题
 
 一个主题可以在以 `vuepress-theme-xxx` 的形式发布到 npm，你可以这样使用它：