mergetool: Clean up description of files and prompts for merge resolutions
mergetool: Clean up description of files and prompts for merge resolutions

This fixes complaints from Junio for how messages and prompts are
printed when resolving symlink and deleted file merges.

Signed-off-by: "Theodore Ts'o" <4ed386e0495d3e109932df055831d9ec2f824927@mit.edu>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git