feat!: remove recursive dir support for setlocal

[joelim-work]

Reasons for removal

• setlocal in Vim is simple and applies only to the current buffer/window. For lf, this can be extended to apply to a specific directory instead of the current one, but including direct support for recursive directories introduces additional complexity.
• Despite the additional complexity, recursive directories still cannot handle all use cases:
  • Recursion depth cannot be specified setlocal depth/glob specification #1656
  • String matching is not supported (e.g. directories with names starting with foo)
  • Other user-specific rules (e.g. directories containing .git)
• User-specific rules for applying setlocal to directories satisfying some condition can be implemented via on-load hooks (see below for examples)
• The distinction between /homdie/user/foo and /home/user/foo/ is not intuitive for users, as most commands (rsync is a notable exception) treat them as equivalent.

Examples

Apply setlocal to a directory and its subdirectories:

cmd on-load &{{
    root="$HOME"/Downloads
    dir=$(dirname "$1")

    case $dir in
        "$root"|"$root"/*) lf -remote "send $id setlocal $dir info size";;
    esac
}}

Apply setlocal to Git repos:

cmd on-load &{{
    dir=$(dirname "$1")

    if [ -d "$dir"/.git ]; then
        lf -remote "send $id setlocal $dir hidden"
    fi
}}