langtools/src/jdk.jshell/share/classes/jdk/internal/jshell/tool/resources/l10n.properties

The value for properties key help.retain.mode was broken as missing the '\' for second line.

Current:
help.retain.mode = \
Retain the existence and configuration of a user-defined feedback mode.\n\
This mode will be available in this and future sessions of the jshell tool.
\n\t\
/retain mode <mode>\n\
\n\
Where <mode> is the name of a mode you wish to retain.\n\
The <mode> must previously have been created with /set mode and\n\
configured as desired with /set prompt, /set format, and /set truncation.\n

Expect:
help.retain.mode = \
Retain the existence and configuration of a user-defined feedback mode.\n\
This mode will be available in this and future sessions of the jshell tool.\n\t\
/retain mode <mode>\n\
\n\
Where <mode> is the name of a mode you wish to retain.\n\
The <mode> must previously have been created with /set mode and\n\
configured as desired with /set prompt, /set format, and /set truncation.\n

After correction, help.retain.mode has a correct multiple value. Otherwise, the /retain will be recognized as a key.