lef: make warning about 'FOREIGN differs from MACRO name' more informative

Warning: FOREIGN name differs from MACRO name in macro: NAME (line=15661, cell=NAME, file=lef.gz)

looking at the lef file:

MACRO NAME
  FOREIGN NEW ;
..

it would be nice if the warning would state the foreign name that differs and it can be shorted in the process too. E.g.:

Warning: FOREIGN name NEW differs from MACRO name NAME (line=15661, file=lef.gz)