flush output of unexpand command as well

src/uu/expand/src/expand.rs

@@ -244,10 +244,10 @@ fn expand(options: Options) {
                     }
                 }
 
-                safe_unwrap!(output.flush());
                 byte += nbytes; // advance the pointer
             }
 
+            safe_unwrap!(output.flush());
             buf.truncate(0); // clear the buffer
         }
     }

src/uu/unexpand/src/unexpand.rs

@@ -324,6 +324,7 @@ fn unexpand(options: Options) {
 
             // write out anything remaining
             write_tabs(&mut output, ts, scol, col, pctype == Tab, init, true);
+            safe_unwrap!(output.flush());
             buf.truncate(0); // clear out the buffer
         }
     }