OcdFileExport: Harmonize warning messages

[dl3sdo]

Warning messages were not consistent regarding whether

• the symbol name is quoted (text symbols were unquoted)
• they end with a dot
• details are separated by a comma or a colon

[dl3sdo]

Regarding consistency:
.ocd import has a different style, e.g.
In line symbol 862.0 'Treppe': Skipped secondary point symbol.

[dg0yt]

• This affects translations. Without manual edits, existing translations are no longer used, immediately.
• OcdFileImport has overloads addSymbolWarning for (OCD) symbol types which use per-type variants of "In area symbol %1 '%2': %3" to decouple the repeated text from the individual details. Maybe this is a pattern to adopt and adopt in other places.