prune.c: Comment about the original PP Pruning comments
prune.c: Comment about the original PP Pruning comments

ampli/link-grammar,linas/link-grammar,linas/link-grammar,linas/link-grammar,ampli/link-grammar,opencog/link-grammar,opencog/link-grammar,linas/link-grammar,ampli/link-grammar,opencog/link-grammar,linas/link-grammar,opencog/link-grammar,ampli/link-grammar,linas/link-grammar,ampli/link-grammar,linas/link-grammar,opencog/link-grammar,opencog/link-grammar,ampli/link-grammar,ampli/link-grammar,linas/link-grammar,ampli/link-grammar,ampli/link-grammar,opencog/link-grammar,opencog/link-grammar,opencog/link-grammar,linas/link-grammar