H/M/L cause code folds to expand

[awan1]

To reproduce:

• Fold some code on screen
• Use H/M/L commands to move cursor

Expected result:

• The cursor moves to the top/middle/bottom of the screen without expanding folded code

Actual result:

• The cursor moves into folded code and expands it.

Guess at a cause: if H/M/L moves by calculating the number of lines shown on the screen and moving the cursor accordingly, it will move into the folded code section.