I am trying to typeset a two-column text in a right-to-left language using
ConTeXt. Because I want footnotes in this text to be set ragged-bottom, I
am using pagecolumns instead of standard columns. I also want to track the
first and last textual division markers on each page using markings.
Combining all of these ingredients seems to create a problem in ConTeXt:
when the pagecolumns are set in right-to-left order, the top and bottom
marks fetched are always the top and bottom marks in the left column, while
the true top mark should be the top mark of the right column. I've observed
this behavior using text in an actual right-to-left language, but the
following minimal (non-)working example with an English sample text
demonstrates the same behavior:

```
%Create a new markset to use:
\definemarking[TestMark]
%Setup header to reflect top and bottom marks:
\setupheadertexts[top: {\fetchmark[TestMark][top]}][bottom:
{\fetchmark[TestMark][bottom]}][top: {\fetchmark[TestMark][top]}][bottom:
{\fetchmark[TestMark][bottom]}] %even left, even right, odd left, odd right
%Setup the columns layout:
\definepagecolumns [example] [
    n=2, %number of columns
    direction=reverse, %does not work if ending comma is removed!
]
\starttext
\startpagecolumns[example]
    \marking[TestMark]{1}(1) \input knuth\par
    \marking[TestMark]{2}(2) \input knuth\par
    \marking[TestMark]{3}(3) \input knuth\par
    \marking[TestMark]{4}(4) \input knuth\par
    \marking[TestMark]{5}(5) \input knuth\par
    \marking[TestMark]{6}(6) \input knuth\par
    \marking[TestMark]{7}(7) \input knuth\par
    \marking[TestMark]{8}(8) \input knuth\par
\stoppagecolumns
\stoptext
```

I typeset this using ConTeXt version 2020.03.10, as released with TeXLive
2020. As my comment in the MWE points out, there also seems to be a bug in
the key-value parsing of \definepagecolumns that causes it not to parse the
direction=reverse input unless it is followed by a comma.

Is there some way I can improve my syntax to avoid this issue, or is it
just a bug that needs to be fixed? I've tried fetching other marks (e.g.,
first and last), but the only marks that ConTeXt seems to find are the ones
for the left column.

Thank you,

Joey