plot_linewidths() plots frequencies

Branch: develop

File: experiments/eigen/result.py

Function: EigenResult.plot_linewidths() (line 520)

Issue: plot_linewidths() plots frequencies

Cause: usage of FREQUENCY_COLUMN_PATTERN, probably due to copypasting plot_frequencies()

https://codebase.helmholtz.cloud/micromagnetic-modeling/tetrax/-/blob/develop/tetrax/experiments/eigen/result.py?ref_type=heads#L574

Suggested fix: at line 574, replace FREQUENCY_COLUMN_PATTERN with LINEWIDTH_COLUMN_PATTERN