GH Actions: tweaks for the markdown QA check

Looks like the `remark-lint` project has released a new version fixing the bug causing the failing build earlier this week.

This commit reverts the rule change from PR 124.

Refs:
* https://github.com/remarkjs/remark-lint/releases/tag/9.1.2
* remarkjs/remark-lint@639271a

.remarkrc

@@ -24,6 +24,7 @@
     "remark-lint-no-unneeded-full-reference-link",
     "remark-lint-no-unused-definitions",
     ["remark-lint-strikethrough-marker", "~~"],
+    ["remark-lint-table-cell-padding", "consistent"],
     "remark-lint-table-pipe-alignment",
     "remark-lint-heading-whitespace",
     "remark-lint-list-item-punctuation",