[clang] Add alternative email for steakhal (llvm#128558)

Both steakhal and balazs-benics-sonarsource accounts are mine. See
llvm#125859

Author: steakhal

clang/Maintainers.rst

@@ -136,6 +136,7 @@ Clang static analyzer
 
 | Balázs Benics
 | benicsbalazs\@gmail.com (email), steakhal (Phabricator), steakhal (GitHub)
+| balazs.benics\@sonarsource.com (email), balazs-benics-sonarsource (GitHub)
 
 Compiler options
 ~~~~~~~~~~~~~~~~