Add .gitattributes file

[schuenke]

As for example seen in #351, different line endings (CRLF vs. LF) lead to Git considering every line to be modified, resulting in a diff that shows way more than the actual code changes.

Using the .gitattributes file added in this PR should force line ending to be LF in all python and markdown files and thus fix this issue in future PRs.

The diff=python and diff=markdown should additionally improve the diff output.

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
/home/runner/.local/lib/python3.12/site-packages/pypulseq
add_gradients.py	137	60	56%	44, 52, 58, 61, 75–86, 92, 125–128, 135–136, 155, 162, 167–263
add_ramps.py	36	36	0%	1–92
align.py	35	4	89%	41, 45, 69, 73
calc_duration.py	25	1	96%	37
calc_ramp.py	220	216	2%	48–359
calc_rf_bandwidth.py	37	28	24%	45–81, 85–89
check_timing.py	96	29	70%	78, 82, 107, 180, 199, 232, 239, 249–293
compress_shape.py	30	1	97%	28
convert.py	40	8	80%	42, 48, 66, 72–73, 82, 88–89
event_lib.py	96	14	85%	6–9, 48–51, 70–71, 205–210
make_adc.py	98	14	86%	77, 80, 90–94, 97, 146, 149, 153, 159, 163, 202, 204, 206, 214
make_adiabatic_pulse.py	132	39	70%	204–208, 228–232, 240–241, 264, 270, 339–358, 462–471, 509–517
make_arbitrary_grad.py	53	15	72%	71, 74, 77, 80, 96–98, 107, 109, 117–121, 130
make_arbitrary_rf.py	75	63	16%	95–179
make_block_pulse.py	48	3	94%	121–125, 128
make_delay.py	9	1	89%	27
make_digital_output_pulse.py	16	2	88%	42, 50
make_extended_trapezoid.py	56	12	79%	67, 70, 76, 82, 85, 88, 91, 94, 116, 134, 136, 139
make_extended_trapezoid_area.py	93	3	97%	52, 227, 230
make_gauss_pulse.py	73	20	73%	139–143, 146–170, 177, 180
make_label.py	22	4	82%	64, 66, 68, 75
make_sigpy_pulse.py	119	30	75%	12–13, 121, 124, 128, 165–169, 173, 176–177, 180–181, 196, 203, 208, 220, 223, 248–258, 272, 275, 305–315
make_sinc_pulse.py	70	10	86%	102, 108, 136–140, 144, 147–148, 151–152, 174
make_soft_delay.py	26	2	92%	107, 125
make_trapezoid.py	111	7	94%	177, 190, 196, 214, 232, 237, 255
make_trigger.py	16	2	88%	47, 55
opts.py	66	9	86%	78, 83, 102, 142, 166–170
points_to_waveform.py	9	1	89%	27
rotate.py	69	14	80%	15, 55, 66–69, 85–90, 112, 119–120
scale_grad.py	30	1	97%	65
sigpy_pulse_opts.py	26	7	73%	34–41
split_gradient.py	39	31	21%	46–103
split_gradient_at.py	70	27	61%	63–90, 110, 114, 118–120, 154–156
traj_to_grad.py	13	9	31%	26–40
/home/runner/.local/lib/python3.12/site-packages/pypulseq/SAR
SAR_calc.py	5	1	80%	9
/home/runner/.local/lib/python3.12/site-packages/pypulseq/Sequence
block.py	469	79	83%	63, 66, 74, 80, 95, 103, 109, 120, 123, 126, 134, 139, 148, 159, 167, 207, 209, 213, 225, 274, 278, 294, 319–345, 382–385, 421–429, 436, 466–470, 512, 518, 551, 587–594, 611, 621, 647, 685, 703, 706, 724, 738, 765, 844, 881, 905
calc_grad_spectrum.py	81	76	6%	68–190
calc_pns.py	40	31	22%	45–96
ext_test_report.py	144	11	92%	61, 138, 149–150, 237–243
install.py	75	42	44%	31, 52, 69, 71, 112–131, 148, 181–184, 200–212, 254–278
parula.py	4	2	50%	19–86
read_seq.py	394	37	91%	44–45, 110, 117, 130, 133–134, 138, 184, 228, 401, 422–439, 502, 505, 590, 614, 654, 696–700, 815, 826
sequence.py	629	130	79%	10–13, 105–115, 136–149, 196, 261–264, 311, 338, 355, 403, 431, 458–463, 500, 516, 607, 635–644, 656, 678, 719–722, 776, 814, 825–826, 832, 843, 849, 851, 859, 892–900, 1030, 1120, 1126, 1129, 1132, 1169, 1294–1307, 1337, 1365, 1387–1389, 1410, 1473, 1481, 1548, 1559–1572, 1641–1642, 1653–1671, 1695, 1725–1733, 1769, 1783–1793, 1808
write_seq.py	362	17	95%	45, 69, 72–79, 313, 339, 342–349, 499
/home/runner/.local/lib/python3.12/site-packages/pypulseq/utils
cumsum.py	14	1	93%	17
paper_plot.py	63	58	8%	47–130
safe_pns_prediction.py	126	113	10%	50–87, 102–189, 197–214, 222, 244–250, 279–286, 310–336, 344–383, 396–411, 415
seq_plot.py	378	180	52%	20, 98, 130–131, 150, 167–169, 174–216, 226–233, 240–305, 309–315, 319–327, 349, 351, 354, 379–401, 446–447, 450–453, 485, 500–510, 519–521, 539–541, 543–544, 546–547, 580–592, 607–608, 624–641, 682–686
tracing.py	16	6	62%	33–34, 42, 54–55, 75
/home/runner/.local/lib/python3.12/site-packages/pypulseq/utils/siemens
asc_to_hw.py	58	53	9%	21–28, 48–106
readasc.py	48	45	6%	25–100
TOTAL	5103	1605	69%

Tests	Skipped	Failures	Errors	Time
1396	21 💤	0 ❌	0 🔥	4m 51s ⏱️

[mcencini]

It sounds like a great idea