Center tables within markdown

[ollien]

This fixes tables not being centered in markdown files, as described by #4916.

Before:

After:

I tried to avoid using !important, but Semantic seems to place a text-align: inherit on tables, so I had to (sadly) resort to using it.

[lafriks]

I don't think this is the desired solution always

[ollien]

Could you elaborate? It seems consistent with GitHub's markdown, which is what the original issue proposed.

[lafriks]

Current proposed solution would center also tables that should not be centered.

Example

| 参数 | 类型 | 说明 | 是否必填 |
| :----: | :----: | :----: | :----: |
| code | string | 机构编码  | 是 |

Should be centered and look like this:

参数	类型	说明	是否必填
code	string	机构编码	是

While standard tables should not be centered. Example:

| 参数 | 类型 | 说明 | 是否必填 |
| ---- | ---- | ---- | ---- |
| code | string | 机构编码  | 是 |

参数	类型	说明	是否必填
code	string	机构编码	是

[lafriks]

This will break standard table layout

[ollien]

Got it. Did not realize there was a difference.

[techknowlogick]

Closing per @lafriks comment.