TYraitement erreur saisie assiduité + cosmetic

app/scodoc/html_sidebar.py

app/scodoc/sco_page_etud.py

app/scodoc/sco_utils.py

app/static/css/assiduites.css

app/static/css/scodoc.css

app/templates/assiduites/explication_etats_justifs.j2

app/templates/assiduites/pages/ajout_justificatif_etud.j2

app/templates/assiduites/pages/bilan_etud.j2

app/templates/assiduites/pages/calendrier_assi_etud.j2

app/templates/assiduites/pages/signal_assiduites_group.j2

app/templates/sidebar.j2

app/views/assiduites.py