Allow "Mbed TLS" as the project name in Doxygen

Previously the code only recognized the old spelling "mbed TLS", so it
missed doxygen/input/doc_mainpage.h.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

scripts/bump_version.sh

@@ -142,7 +142,7 @@ mv tmp tests/suites/test_suite_version.data
 [ $VERBOSE ] && echo "Bumping PROJECT_NAME in doxygen/mbedtls.doxyfile and doxygen/input/doc_mainpage.h"
 for i in doxygen/mbedtls.doxyfile doxygen/input/doc_mainpage.h;
 do
-  sed -e "s/mbed TLS v[0-9\.]\{1,\}/mbed TLS v$VERSION/g" < $i > tmp
+  sed -e "s/\\([Mm]bed TLS v\\)[0-9][0-9.]*/\\1$VERSION/g" < $i > tmp
   mv tmp $i
 done