The lenient docstrings of Site_Factors and Site_Effect_Adjustment describe the opposite of what the code does #91

Found while reviewing #74. Pre-existing on main (b764057); #74 does not change the behavior.

Problem

Both docstrings say that out-of-range Vs30, z1 and PGA values are clipped to the closest bound "if False":

The code does the opposite. With lenient=False (the default) it raises ValueError; it clips only with lenient=True. Site_Effect_Adjustment passes lenient on to Site_Factors unchanged:

from PySeismoSoil.class_site_factors import Site_Factors

try:
    Site_Factors(170, 100, 0.3, lenient=False)
except ValueError as e:
    print('lenient=False ->', e)
# lenient=False -> Vs30 should be between [175, 950] m/s

sf = Site_Factors(170, 100, 0.3, lenient=True)
print('lenient=True ->', sf.Vs30)
# lenient=True -> 175

Fix

1. In both docstrings, describe the actual behavior, for example: "Whether to accept Vs30, z1, and PGA values outside the valid range. If False, such values raise a ValueError. If True, they are treated as the closest boundary values (e.g., Vs30 = 170 m/s is treated as 175 m/s). This option does not apply to invalid Vs30-z1 combinations, which always raise a ValueError."
2. No code or test change is needed.