Log Message:
tex-koma-script: update to 3.26a

Most significant changes:

- \DeclareSectionCommand etc. provide new options `runin` and
  `afterindent`. This also makes it possible to use a negative skip
  before or after the headings.

- Better support of XeLaTeX  by scrlayer-notecolumn.

- \@setplength, \@newplength and \@addtoplength are deprecated and
  replaced by \setplength, \newplength and \addtoplength

- scrlttr2 and scrletter provide new commands \setplengthtowith,
\setplengthtoheight, \setplengthtodepth, \setplengthtototalheight.

- tocbasic provides \DeclareTOCStyleEntries to declare/modify multiple
  toc levels with one single command.

- Several additional, minor changes.

- Several bug fixes.