grep only matching part of tags to prevent duplicates

metrics/scripts/build_metrics.sh

@@ -4,9 +4,9 @@ links=0
 images=0
 
 # count number of links
-links=$(find . -type d -path './.sphinx' -prune -o -name '*.html' -exec cat {} + | grep "<a " | wc -l)
+links=$(find . -type d -path './.sphinx' -prune -o -name '*.html' -exec cat {} + | grep -o "<a " | wc -l)
 # count number of images
-images=$(find . -type d -path './.sphinx' -prune -o -name '*.html' -exec cat {} + | grep "<img " | wc -l)
+images=$(find . -type d -path './.sphinx' -prune -o -name '*.html' -exec cat {} + | grep -o "<img " | wc -l)
 
 # summarise latest metrics
 echo "Summarising metrics for build files (.html)..."