Fix doc-view conversion indicator for svg images

* lisp/doc-view.el (doc-view-pdf->png-converter-mupdf): Show the
correct pdf->svg indicator when producing svg images.  (Bug#62713)
1 job for master in 6 minutes and 19 seconds (queued for 14 seconds)
Status Job ID Name Coverage
  Normal
failed #74894
test-lisp-inotify

00:06:19

 
Name Stage Failure
failed
test-lisp-inotify Normal
$ find ${test_name} ! \( -name "*.log" -o -name ${EMACS_TEST_JUNIT_REPORT} \) -type f -delete
$ find ${test_name} -type d -depth -exec rmdir {} + 2>/dev/null
Uploading artifacts...
test-lisp-inotify-f0abc9bc/: found 120 matching files
Uploading artifacts to coordinator... ok
id=74894 responseStatus=201 Created token=voFYAtYf
Uploading artifacts...
test-lisp-inotify-f0abc9bc/junit-test-report.xml: found 1 matching files

Uploading artifacts to coordinator... ok
id=74894 responseStatus=201 Created token=voFYAtYf
ERROR: Job failed: exit code 2