Issue #381: Rename linelist argument to data

[athowes]

Description

This PR closes #381.

The only case where something is called linelist are this simulation function, and the observe_process function. We are expecting to remove observe_process with issue #431.

Checklist

• My PR is based on a package issue and I have explicitly linked it.
• I have included the target issue or issues in the PR title in the for Issue(s) issue-numbers: PR title
• I have read the contribution guidelines.
• I have tested my changes locally.
• I have added or updated unit tests where necessary.
• I have updated the documentation if required.
• My code follows the established coding standards.
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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.11%. Comparing base (d02c7c7) to head (0ba1076).
Report is 51 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #437      +/-   ##
==========================================
+ Coverage   88.55%   94.11%   +5.56%     
==========================================
  Files          11       16       +5     
  Lines         402      425      +23     
==========================================
+ Hits          356      400      +44     
+ Misses         46       25      -21     

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