traduccion de reference/grammar.po (#3319)

Closes #3290

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Co-authored-by: Manuel Kaufmann <humitos@gmail.com>
Co-authored-by: Cristián Maureira-Fredes <cmaureir@users.noreply.github.com>
Co-authored-by: Cristián Maureira-Fredes <cristian.maureira-fredes@qt.io>

Author: 3 people