Add mermaid support to the document. Consider add mermaid.js to local (not from requesting unpkg.org?)

Author: ustcljh

docs/Ch05/index.md

@@ -318,7 +318,7 @@ drwxrwxr-x 2 ustc ustc 4096 Feb  3 22:38 a_folder
 而 UNIX 系列采用了一种不一样的思路组织文件：整个系统的文件都从 `/`（根目录）开始，像一棵树一样，类似于下图。
 
 ```mermaid
-graph TD
+graph LR
     / --> bin
     / --> boot
     / --> dev
@@ -348,7 +348,7 @@ graph TD
     lisi --> docs
 
     mnt --> windows_disk
-    subgraph
+    subgraph mount
     windows_disk --> Windows
     windows_disk --> Users
     end

mkdocs.yml

@@ -46,13 +46,19 @@ markdown_extensions:
   - pymdownx.emoji:
       emoji_index: !!python/name:material.extensions.emoji.twemoji
       emoji_generator: !!python/name:material.extensions.emoji.to_svg
+  - pymdownx.superfences:
+      custom_fences:
+      - name: mermaid
+        class: mermaid
+        format: !!python/name:mermaid2.fence_mermaid_custom
   - pymdownx.inlinehilite
   - pymdownx.keys
   - pymdownx.superfences
   - markdown.extensions.def_list
   - toc:
       permalink: true
 
+
 extra:
   social:
     - icon: octicons/globe-16
@@ -63,6 +69,10 @@ extra:
     provider: google
     property: G-Q8WSZQS8E1
 
+plugins:
+  - mermaid2:
+      javascript: https://unpkg.com/mermaid@10.4.0/dist/mermaid.esm.min.mjs 
+
 extra_css:
   - 'css/extra.css'
   - 'https://101.lug.ustc.edu.cn/_extra/roboto.css'

requirements.txt

@@ -1,3 +1,4 @@
 mkdocs>=1.5.3
 mkdocs-material>=9.4.6
 jieba
+mkdocs-mermaid2-plugin