Update ecg_process.py

[BeardedBioelectronics]

Fixed typo re: ECG peak info dict key

Description
This PR is just a basic typo fix in the comments and a test run before more significant contributions.

Proposed Changes
I changed a comment to accurately describe the key used for ECG Peaks in info

Checklist
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[X ] I have read the CONTRIBUTING file.
[ X] My PR is targetted at the dev branch (and not towards the master branch).
[ N/A] I ran the CODE CHECKS on the files I added or modified and fixed the errors.
[ N/A] I have added the newly added features to News.rst (if applicable)

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[codecov-commenter]

Codecov Report

Patch coverage has no change and project coverage change: +0.04 🎉

Comparison is base (690eac7) 53.83% compared to head (ee7079f) 53.87%.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #836      +/-   ##
==========================================
+ Coverage   53.83%   53.87%   +0.04%     
==========================================
  Files         295      295              
  Lines       13802    13802              
==========================================
+ Hits         7430     7436       +6     
+ Misses       6372     6366       -6     

Impacted Files	Coverage Δ
neurokit2/ecg/ecg_process.py	100.00% <ø> (ø)

... and 2 files with indirect coverage changes

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[danibene]

This looks good to me, thank you for the fix 😃

[welcome]

Congrats on merging your first pull request! 🎉🍾 We're looking forward to your next one!