Fix insuficient digits when displaying the tilt matrix

[tturpin]

Description

This increases the number of digits used for displaying the tilt matrix in G29 V2 and M420 S1 V from 2 to 4. This is important because the coefficients are expected to be very low, even for a significantly tilted bed, and the matrix would look like the identity matrix otherwise.

Requirements

None

Benefits

Avoids displaying a misleading identity tilt matrix in verbose calls to G29 and M420 which would suggest that leveling somehow failed.

Output with only two digits:

> G29 V2
SENDING:G29 V2
G29 Auto Bed Leveling
Probing mesh point 3/25.
Probing mesh point 7/25.
Probing mesh point 8/25.
Probing mesh point 9/25.
Probing mesh point 11/25.
Probing mesh point 12/25.
Probing mesh point 13/25.
Probing mesh point 14/25.
Probing mesh point 15/25.
Probing mesh point 17/25.
Probing mesh point 18/25.
Probing mesh point 19/25.
Probing mesh point 23/25.
Eqn coefficients: a: 0.00125742 b: 0.00181860 d: 0.92799848
Bed Level Correction Matrix:
+1.00 +0.00 +0.00
-0.00 +1.00 +0.00
-0.00 -0.00 +1.00
> M420 S1 V
SENDING:M420 S1 V
Bed Level Correction Matrix:
+1.00 +0.00 +0.00
-0.00 +1.00 +0.00
-0.00 -0.00 +1.00
Bed Leveling ON

Output with four digits:

> G29 V2
SENDING:G29 V2
G29 Auto Bed Leveling
Probing mesh point 3/25.
Probing mesh point 7/25.
Probing mesh point 8/25.
Probing mesh point 9/25.
Probing mesh point 11/25.
Probing mesh point 12/25.
Probing mesh point 13/25.
Probing mesh point 14/25.
Probing mesh point 15/25.
Probing mesh point 17/25.
Probing mesh point 18/25.
Probing mesh point 19/25.
Probing mesh point 23/25.
Eqn coefficients: a: 0.00124202 b: 0.00187187 d: 0.92893869
Bed Level Correction Matrix:
+1.0000 +0.0000 +0.0012
-0.0000 +1.0000 +0.0019
-0.0012 -0.0019 +1.0000
> M420 S1 V
SENDING:M420 S1 V
Bed Level Correction Matrix:
+1.0000 +0.0000 +0.0012
-0.0000 +1.0000 +0.0019
-0.0012 -0.0019 +1.0000
Bed Leveling ON