Revise ./shell/mf to open both the .docs.md and the .md file upon entering.

[rsyi]

Currently, opening a table entry selected in mf will open the .docs.md file, but this means that for tables with many columns or for small screens, you may not be able to see all the basic metadata. This is an edge case, but in this case the current only workaround is to run mf --a. We might want to consider changing the default behavior to just open both files, but make the .md metadata stub read-only. Ideally, these would show up in a split pane setup.

In vim, you can run vim -o to open two splits, which we really ought to do (with the focus on the .docs.md split). But we need to add some case statements to ensure that, for users not using vim, the resulting behavior is reasonable.

[rsyi]

Turns out fzf supports scrolling in the preview window, so I think there's no longer a real need for this. Closing.