Documentation contribution guidelines lack explanation of the symbol to `(+)` and `(?)`

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• According to https://github.com/apache/shardingsphere/discussions/25951 's discussion , documentation contribution guidelines lack explanation of the symbol to (+) and (?).
• I checked https://github.com/apache/shardingsphere/blob/5ad75d38ab4fcf169a1a4704be4e671200d02e4c/CODE_OF_CONDUCT.md and didn't see an explanation of this symbol.
• These symbols appear on documentation pages like https://shardingsphere.apache.org/document/5.4.0/en/user-manual/common-config/props/ .