Make text e-mails consistent with HTML ones in UserMailer (#6291)

app/views/user_mailer/confirmation_instructions.ar.text.erb

app/views/user_mailer/confirmation_instructions.ca.text.erb

app/views/user_mailer/confirmation_instructions.en.text.erb

app/views/user_mailer/confirmation_instructions.es.text.erb

app/views/user_mailer/confirmation_instructions.fa.text.erb

app/views/user_mailer/confirmation_instructions.fi.text.erb

app/views/user_mailer/confirmation_instructions.fr.text.erb

app/views/user_mailer/confirmation_instructions.he.text.erb

app/views/user_mailer/confirmation_instructions.id.text.erb

app/views/user_mailer/confirmation_instructions.it.text.erb

app/views/user_mailer/confirmation_instructions.ja.text.erb

app/views/user_mailer/confirmation_instructions.ko.text.erb

app/views/user_mailer/confirmation_instructions.nl.text.erb

app/views/user_mailer/confirmation_instructions.no.text.erb

app/views/user_mailer/confirmation_instructions.oc.text.erb

app/views/user_mailer/confirmation_instructions.pl.text.erb

...iews/user_mailer/confirmation_instructions.pt-BR.text.erb

app/views/user_mailer/confirmation_instructions.ru.text.erb

...ws/user_mailer/confirmation_instructions.sr-Latn.text.erb

app/views/user_mailer/confirmation_instructions.sr.text.erb