DOC:Remove DataFrame.append from the 10min intro
Remove the `append` section from 10 min intro doc as complexity of that is very different than `list.append`

- [x] closes #27518


As a note, the DataFrame.append API docs have a good discussion of this https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.append.html#pandas.DataFrame.append.

We need to determine whether the "append" use-case (incrementally building a DataFrame) is important enough to warrant inclusion in the 10min intro. I think as we already have explained `concat` at https://pandas.pydata.org/pandas-docs/stable/getting_started/10min.html#concat, it should suffice for a beginner and it is anyway better than iteratively using `append`.   I'd prefer a warning and link to append docs about performance rather than outright removal CI should be fixed if you fetch and merge master then push.

> I'd prefer a warning and link to append docs about performance rather than outright removal

Note that we do still discuss DataFrame.append in the user guide: https://pandas.pydata.org/pandas-docs/stable/user_guide/merging.html#concatenating-using-append. I just don't think it's valuable enough to include in your first 10 minutes to learning pandas.

That said, we may want to head of the style of iteratively building a DataFrame, like you would with a list, by leaving a comment at the bottom of https://pandas.pydata.org/pandas-docs/stable/getting_started/10min.html#object-creation saying something like

> Adding a column to a DataFrame is relatively fast. Adding a row, however, requires a full copy of the data and a construction of a new Index, which may be expensive. Rather than iteratively building a DataFrame by appending records, we recommend passing the pre-built list of records to the DataFrame constructor. See ... for more.

How does that sound @WillAyd? Sounds good! @jreback I have made the required changes. @TomAugspurger Done! Thanks @sameshl!