terminal: config -list to print strings inside interfaces in quotes (#2680)
terminal: config -list to print strings inside interfaces in quotes (#2680)

Commit 3d6bbbe9 made "config -list" print strings in quotes to avoid
the strings being interpreted as terminal escape codes.  This commit
does the same for "source-list-line-color", which is a raw interface.
This fixes "config -list" with a config like

	source-list-line-color: "\x1b[34m"

The "int" variant is already printed correctly, so just use the
default case for that.
go-delve/delve,go-delve/delve,go-delve/delve,go-delve/delve,go-delve/delve