Cleanup spacing, commentary

Marlin/planner.h

@@ -531,7 +531,7 @@ class Planner {
       if (blocks_queued()) {
         block_t * const block = &block_buffer[block_buffer_tail];
 
-        // If the trapezoid of this block has to be recalculated, it's not save to execute it.
+        // If the block has no trapezoid calculated, it's unsafe to execute.
         if (movesplanned() > 1) {
           block_t* next = &block_buffer[next_block_index(block_buffer_tail)];
           if (TEST(block->flag, BLOCK_BIT_RECALCULATE) || TEST(next->flag, BLOCK_BIT_RECALCULATE))