Fix a bug introduced in d4a5bed.
Though '--mixed' is the default for 'git reset', using it with paths
returns the following warning.
warning: --mixed with paths is deprecated; use 'git reset -- <paths>'
instead.
The terms 'prompt' and 'rprompt' are not always appropriate.
A multi-line theme may choose 'line-one' and 'line-two' instead.
@ColinHebert contributed to this commit.
Colin Hebert
Sorin Ionescu