chore: encourage return types in function definitions

[samayer12]

Description

Encourage non-test code to specify return types.

Related Issue

Hotifx

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Unit, Journey, E2E Tests, docs, adr added or updated as needed
• Contributor Guide Steps followed

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.53%. Comparing base (73341c6) to head (0057fd7).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1364   +/-   ##
=======================================
  Coverage   79.53%   79.53%           
=======================================
  Files          39       39           
  Lines        1818     1818           
  Branches      387      396    +9     
=======================================
  Hits         1446     1446           
- Misses        343      370   +27     
+ Partials       29        2   -27     

see 7 files with indirect coverage changes

[schaeferka]

Nice! This will help us track down these issues.

[samayer12]

This PR would make the logs pretty noisy, but is useful for the project. After discussion with @btlghrants, we're opted to put this on hold while we work on other outstanding refactors (e.g., #1248, #1371, #1250, #1247, etc). This PR will be suitable to revisit once the existing set of linter warnings are resolved.