docs: repaint the figures and update the table in sql/dql/window_clause

[michelle-qinqin]

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)
  docs

• What is the current behavior? (You can also link to an open issue here)

• What is the new behavior (if this is a feature change)?
  repaint the figures and update the table in sql/sql/window_clause

[lumianph]

since there are quite a lot changes in this PR, let's review this PR in the next PR meeting @michelle-qinqin @dl239
@aceforeverd @vagetablechicken pls help carefully review the changes, especially the figures

[aceforeverd]

• 多了个 ppt ?
• window_max_size.png: 4-5s preceding -> 5s preceding

[michelle-qinqin]

ppt是可编辑的图片源文件，之前没有找到可编辑的原文件，我就重画了一个，传上来也方便后续修改。
maxsize的那个是我没注意到，我重新画一下。

[michelle-qinqin]

@aceforeverd 图片已修改，感谢指正~

[aceforeverd]

window_union_2_table: 从下往上第三行应该是 1s preceding

[aceforeverd]

ppt是可编辑的图片源文件，之前没有找到可编辑的原文件，我就重画了一个，传上来也方便后续修改。 maxsize的那个是我没注意到，我重新画一下。

那应该保存一个就可以。原版图片应该使用 draw.io 画的

[michelle-qinqin]

w.i

好的，我删掉en里的可以吗

[aceforeverd]

w.i

好的，我删掉en里的可以吗

都可以

[michelle-qinqin]

window_union_2_table 有效窗口内倒数第三行已修正
en版本里的ppt文件已删除

[aceforeverd]

TODO later: draw a graph for exclude current_row after #2195