fix: strip whitespace from all plural values in handle_plural_values

[lil-aditya]

Summary

Refactored the handle_plural_values() method to simplify plural value parsing and whitespace handling.

Problem

The previous implementation used a manual loop to remove leading whitespace after splitting the string:

values = plural_value.split(";")

for i in range(len(values)):
    current = i + 1
    if current < len(values):
        clean_value = values[current].lstrip()
        values[current] = clean_value

Fixes #283