Merge pull request #2 from pantras/more-scrolling

Update ch5_moving_in_file.md

ch5_moving_in_file.md

@@ -225,6 +225,12 @@ Ctrl-y  scroll up a line
 Ctrl-u  scroll up half screen
 Ctrl-b  scroll up whole screen
 ```
+You can also scroll relatively to the current line:
+```
+zt bring the current line near the top of your screen
+zh bring the current line to the middle (half) of your screen
+zb bring the current line near the bottom of your screen
+```
 
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