test: simpler metacov.ini because of relative_file fixes

Author: nedbat

metacov.ini

@@ -10,6 +10,7 @@
 branch = true
 data_file = ${COVERAGE_METAFILE?}
 parallel = true
+relative_files = true
 source =
     ${COVERAGE_HOME-.}/coverage
     ${COVERAGE_HOME-.}/tests
@@ -91,7 +92,6 @@ title = Coverage.py metacov
 [paths]
 source =
     .
-    *\coverage\trunk
     */coverage/trunk
     # GitHub Actions on Ubuntu uses /home/runner/work/coveragepy
     # GitHub Actions on Mac uses /Users/runner/work/coveragepy