#436 fixed incorrect bit width calculation

[JayPankajPatel]

Issue

writeBusDcls() in liberty/LibertyWriter.cc computes bit_width incorrectly for ascending bus ranges (e.g. [0:10]).

Root Cause

// before — +1 inside abs(), wrong for ascending ranges
std::abs(dcl->from() - dcl->to() + 1)
// ascending  [0:10]:  abs(0  - 10 + 1) = abs(-9) = 9   ← WRONG
// descending [10:0]:  abs(10 - 0  + 1) = 11             ← correct

// after — +1 outside abs(), correct for both
std::abs(dcl->from() - dcl->to()) + 1
// ascending  [0:10]:  abs(0  - 10) + 1 = 11  ✓
// descending [10:0]:  abs(10 - 0)  + 1 = 11  ✓

Change

One character moved — +1 from inside std::abs() to outside.

Tested against OpenSTA 2.5.0.

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