Enable softwrap in kakoune and fix associated movement issues

softwrap.kak

# Softwrap long lines (and correct for improper kakoune movement behavior)
add-highlighter global/softwrap wrap -word -indent
define-command goto-center -docstring 'Jump to the center of the view' %{
    execute-keys %sh{
        echo $kak_window_range $kak_cursor_line | (
            read y x h w l
            num_lines=$((l-y-(h+1)/2))
            if [ $num_lines -lt 0 ]; then
                echo "${num_lines##-}j"
            elif [ $num_lines -gt 0 ]; then
                echo "${num_lines}k"
            fi
        )
    }
}
define-command view-center -docstring 'Position view so the cursor is centered vertically' %{
    view-bottom
    execute-keys %sh{
        echo $kak_window_range $kak_cursor_line | (
            read y x h w l
            num_lines=$((l-y-(h+1)/2))
            if [ $num_lines -lt 0 ]; then
                echo "${num_lines##-}vk"
            elif [ $num_lines -gt 0 ]; then
                echo "${num_lines}vj"
            fi
        )
    }
}
define-command goto-bottom -docstring 'Jump to the bottom of the view' %{
    execute-keys %sh{
        echo $kak_window_range $kak_cursor_line | (
            read y x h w l
            num_lines=$((y+h-l))
            if [ $num_lines -gt 0 ]; then
                echo "${num_lines##-}j"
            fi
        )
    }
}
define-command view-bottom -docstring 'Position view so the cursor is on the last line' %{
    evaluate-commands %sh{
        echo $kak_window_range $kak_cursor_line $kak_buf_line_count | (
            read y x h w l t
            bottom=$((y+h))
            while test $bottom -ge $l; do
                echo "evaluate-commands %{
                    execute-keys vk
                    echo -to-file $kak_response_fifo %val{window_range}
                }" > $kak_command_fifo

                last="$y $x $h $w"
                read y x h w < $kak_response_fifo
                bottom=$((y+h))
                if [ "$y $x $h $w" = "$last" ]; then
                    break
                fi
            done
            echo "echo -to-file $kak_response_fifo %val{cursor_line}" > $kak_command_fifo
            read l2 < $kak_response_fifo

            if [ $l -ne $l2 ]; then
                echo "execute-keys j"
            fi
        )
    }
}
define-command goto-top -docstring 'Jump to the top of the view' %{
    execute-keys %sh{
        echo $kak_window_range $kak_cursor_line | (
            read y x h w l
            num_lines=$((l-y-1))
            if [ $num_lines -gt 0 ]; then
                echo "${num_lines##-}k"
            fi
        )
    }
}
define-command view-top -docstring 'Position view so the cursor is on the first line' %{
    evaluate-commands %sh{
        echo $kak_window_range $kak_cursor_line | (
            read y x h w l
            top=$((y+1))
            while test $top -lt $l; do
                echo "evaluate-commands %{
                    execute-keys vj
                    echo -to-file $kak_response_fifo %val{window_range}
                }" > $kak_command_fifo

                last="$y $x $h $w"
                read y x h w < $kak_response_fifo

                top=$((y+1))
                if [ "$y $x $h $w" = "$last" ]; then
                    break
                fi
            done
        )
    }
}
map -docstring 'window bottom' global goto b '<esc>:goto-bottom<ret>'
map -docstring 'window center' global goto c '<esc>:goto-center<ret>'
map -docstring 'window top' global goto t '<esc>:goto-top<ret>'
map -docstring 'cursor on bottom' global view b '<esc>:view-bottom<ret>'
map -docstring 'center cursor (vertically)' global view c '<esc>:view-center<ret>'
map -docstring 'cursor on top' global view t '<esc>:view-top<ret>'
map global normal <c-b> ':goto-top<ret>kvb'
map global normal <c-f> ':goto-bottom<ret>jvt'
map global normal <c-u> ':goto-center<ret>vb'
map global normal <c-d> 'vt:goto-center<ret>'

No worries, I'm happy to implement it too once I get around to.
I think C++ in general has gotten much better. I'm quite happy with kak-lsp + clangd. The Kakoune code is mostly very obvious, there are hardly any surprises.

Not yet sure about the exact behavior of <c-u> and <c-d>. My muscle memory was thrown off a bit, perhaps they should have Vim behavior (always maintain the cursor position if possible). That should make it easier to track the cursor while scrolling. I think I'll try that one as preliminary patch.