Don't make the outer table knowl box a horizontal scroll container

Review of PR #20 pointed out that the added `overflow-x: auto` on
`td > .knowl-output` turns the box into a scroll container, which exposes
the scrollable overflow of the absolutely positioned `.knowl-footer`
(`width: 100%` starting after the parent's 10px left padding, plus its own
10px left padding). Measured in the browser, that is 20px of scroll range
on every table knowl, so even a short knowl whose content fits gained a
horizontal scrollbar (box height 123px -> 138px).

The declaration was also redundant: `.knowl-content` already has
`max-width: 100%; overflow: auto` and is the right inner scroller for
over-wide content. Drop `overflow-x` (so the box keeps the inherited
`overflow: hidden`) and reword the comment accordingly.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: roed314

lmfdb/templates/style.css

@@ -1178,11 +1178,10 @@ table .knowl a {
    knowl_click_handler in lmfdb.js).  Inline-size containment keeps that row
    from being counted when the browser computes the column widths, so opening
    a knowl no longer pushes the other columns around (issue #6501): the box
-   simply spans the table's current width.  Content that is still too wide
-   scrolls horizontally inside the box instead of stretching the table. */
+   simply spans the table's current width.  The .knowl-content overflow rule
+   above handles content that is wider than the available box. */
 td > .knowl-output {
   contain: inline-size;
-  overflow-x: auto;
 }
 .knowl-output.loading {
  color: {{color.grey}};