dist/tools/backport_pr: fix typos
dist/tools/backport_pr: fix typos

jasonatran/RIOT,kaspar030/RIOT,miri64/RIOT,OlegHahm/RIOT,kaspar030/RIOT,kaspar030/RIOT,basilfx/RIOT,aeneby/RIOT,toonst/RIOT,miri64/RIOT,kYc0o/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,x3ro/RIOT,yogo1212/RIOT,OTAkeys/RIOT,basilfx/RIOT,smlng/RIOT,mtausig/RIOT,aeneby/RIOT,yogo1212/RIOT,smlng/RIOT,kYc0o/RIOT,toonst/RIOT,OlegHahm/RIOT,yogo1212/RIOT,mtausig/RIOT,OTAkeys/RIOT,miri64/RIOT,basilfx/RIOT,OlegHahm/RIOT,OTAkeys/RIOT,josephnoir/RIOT,x3ro/RIOT,OTAkeys/RIOT,RIOT-OS/RIOT,josephnoir/RIOT,RIOT-OS/RIOT,ant9000/RIOT,jasonatran/RIOT,miri64/RIOT,smlng/RIOT,basilfx/RIOT,toonst/RIOT,RIOT-OS/RIOT,yogo1212/RIOT,kYc0o/RIOT,yogo1212/RIOT,ant9000/RIOT,miri64/RIOT,toonst/RIOT,authmillenon/RIOT,mtausig/RIOT,x3ro/RIOT,x3ro/RIOT,authmillenon/RIOT,kYc0o/RIOT,authmillenon/RIOT,jasonatran/RIOT,basilfx/RIOT,toonst/RIOT,OlegHahm/RIOT,smlng/RIOT,authmillenon/RIOT,x3ro/RIOT,kYc0o/RIOT,ant9000/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,ant9000/RIOT,yogo1212/RIOT,jasonatran/RIOT,jasonatran/RIOT,josephnoir/RIOT,smlng/RIOT,josephnoir/RIOT,mtausig/RIOT,josephnoir/RIOT,aeneby/RIOT,authmillenon/RIOT,aeneby/RIOT,kaspar030/RIOT,OTAkeys/RIOT,ant9000/RIOT,mtausig/RIOT,aeneby/RIOT