Backport PR #5754: Format command name into subcommand_description at run time, not import

This caused an issue if IPython was imported after sys.argv was set to `[]`.
Backport PR #5766: View.map with empty sequence should return empty list

closes #5765
Backport PR #5768: fix cursor keys in long lines wrapped in markdown

closes #5467

pinging @ellisonbg and @jdfreder who reported the bug
Backport PR #5769: Don't urlescape the text that goes into a title tag

If there are spaces in a folder name, you get funny stuff in the `<title>` tag in the tree view. For example, a folder called `/Analysis and Results` will result in the title `<title>Analysis%20and%20Results</title>`.

There's no need for URL escaping the page title.
Backport PR #5788: run cells with `silent=True` in `%run nb.ipynb`

- more consistent with running scripts
- avoids a bunch of uncapturable `Out[n]: ` outputs when running a notebook.

closes #5685
Backport PR #5806: Don't auto-move .config/ipython if symbolic link