Gesture description for "moveToPreviousSiblingForce" is incorrect

[cary-rowen]

Hi @mltony

I may have discovered an oversight while inspecting the code.

The description of "moveToNextSiblingForce" is:
Moves to the next line with the same indentation level as the current line potentially in the following indentation block.

The gesture description of "moveToPreviousSiblingForce" should be similar to the "moveToNextSiblingForce" expression, for example:
Moves to the previous line with the same indentation level as the current line potentially in the preceding indentation block.

In fact, the gesture description of "moveToPreviousSiblingForce" is:
Moves to the previous line with the same indentation level as the current line within the current indentation block.

i will fix it