Write a function count_nonempty_lines(file_path) that receives the path to a text file, reads it using a with open(..., 'r') block, and returns the number of lines that contain at least one non‑whitespace character. Empty lines or lines that only contain spaces/tabs should not be counted.
Example:
# suppose 'sample.txt' contains:
# Line one\n
# \n# Line three\n
print(count_nonempty_lines('sample.txt')) # -> 2