[FIX] *: typos and english incoherences

Mainly transifex issues but also some errors found through 'grep' checks.

Fix typos and obscure english strings in xml contents, fields strings/helps, some docstrings, ...
ensuring correct translations base (and fallback when translations isn't available).

closes odoo/odoo#57276

X-original-commit: 4214f05d454bca2b60fda3a288d529c098e84f77
Related: odoo/enterprise#13053
Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>
Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>

addons/web/static/lib/fullcalendar/core/main.css

@@ -1015,7 +1015,7 @@ Lots taken from Flatly (MIT): https://bootswatch.com/4/flatly/bootstrap.css
     white-space: normal !important;
   }
 
-  /* hide the the time that is normally displayed... */
+  /* hide the time that is normally displayed... */
   .fc-time-grid .fc-event .fc-time span {
     display: none;
   }