[Proposal] Add warning message when setParam fails silently

Description
While working on PEP8 cleanups in netpyne/specs/netParams.py, I noticed that setParam and similar methods fail silently when a label is not found.

Current Behavior

if label in self:
    d = self[label]
else:
    return False  # Silently fails, user is not notified

Proposed Improvement
I propose adding an explicit warning so users can debug their scripts easier:

else:
    print(f\"Warning: Label '{label}' not found. Parameter '{param}' not set.\")
    return False

Question
Should I include this UX improvement as part of the PEP8 cleanup PR, or would you prefer a separate PR for this logic change?"

從 netpyne/specs/netParams.py 開始，閱讀 setParam 以及 issue 中描述的類似方法。確認缺少 label 時的預期行為，然後驗證是否會發出警告，且該方法仍會返回 False 而不設定參數。