add dtx tag patterns

[jlaurens]

in dtx files the sectioning commands are prefixed with a % character and the comment start with ^^A. Only the standard guards readme, install and driver are supported. Other guards may be used dozens of times, which makes the tag tree so big that it becomes unusable.

[codecov[bot]]

Codecov Report

Merging #1001 (ba8fb64) into main (d2229f2) will not change coverage. The diff coverage is n/a.

:exclamation: Current head ba8fb64 differs from pull request most recent head 9f4af91. Consider uploading reports for the commit 9f4af91 to get more accurate results

@@           Coverage Diff           @@
##             main    #1001   +/-   ##
=======================================
  Coverage   34.78%   34.78%           
=======================================
  Files         146      146           
  Lines       17369    17369           
=======================================
  Hits         6042     6042           
  Misses      11327    11327           

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[stloeffler]

Thanks, merged.