Added argument description of space function

[Starlitnightly]

@DBinary Please add argument descriptions to all functions in the space directory that currently lack them.

The format likes:

def Matrix_ID_mapping(data:pd.DataFrame,gene_ref_path:str)->pd.DataFrame:
    """
    Maps gene IDs in the input data to gene symbols using a reference table.

    Arguments:
        data: The input data containing gene IDs as index.
        gene_ref_path: The path to the reference table containing the mapping from gene IDs to gene symbols.

    Returns:
        data: The input data with gene IDs mapped to gene symbols.

    """

[DBinary]

The descriptions have been added in the pull request.