Merge pull request #7571 from smlng/enh/doc/fix_non_ascii

boards/arduino-atmega-common/Makefile.include

boards/msba2-common/tools/armtools.txt

core/include/msg.h

cpu/cc2538/include/periph_cpu.h

cpu/kinetis_common/doc.txt

doc/doxygen/src/mainpage.md

drivers/kw2xrf/kw2xrf_getset.c

drivers/mrf24j40/mrf24j40_getset.c

drivers/tcs37727/include/tcs37727-internal.h

pkg/openthread/include/ot.h

sys/cpp11-compat/include/riot/thread.hpp

sys/hashes/doc.txt

sys/net/gnrc/netapi/gnrc_netapi.c

sys/posix/pthread/include/pthread_mutex.h

tests/driver_hd44780/README.md

tests/shell/main.c