Clean up method return consistency

[gmlewis]

@h2floh pointed out in #2315 that our method returns are inconsistent.
This PR addresses this inconsistency.

@h2floh - please review and LGTM+Approve this PR if you agree to the changes.

[gmlewis]

According to https://githubstatus.com , actions are currently experiencing degraded performance, which is why no tests have run as of yet.

[codecov]

Codecov Report

Merging #2318 (977aa72) into master (1694b79) will increase coverage by 0.09%.
The diff coverage is 100.00%.

@@ Coverage Diff @@## master #2318 +/- ##
==========================================
+ Coverage 97.95% 98.04% +0.09% 
==========================================
Files 117 117 Lines 10402 10460 +58 ==========================================
+ Hits 10189 10256 +67 + Misses 146 140 -6 + Partials 67 64 -3 

Impacted Files	Coverage Δ
github/activity_star.go	100.00% <ø> (ø)
github/gists.go	96.68% <ø> (ø)
github/github.go	97.73% <ø> (ø)
github/orgs_members.go	98.35% <ø> (ø)
github/repos_collaborators.go	100.00% <ø> (ø)
github/repos_contents.go	89.33% <ø> (ø)
github/billing.go	100.00% <100.00%> (ø)
github/git_blobs.go	100.00% <100.00%> (ø)
github/git_tags.go	100.00% <100.00%> (ø)
github/issues_assignees.go	100.00% <100.00%> (ø)
... and 12 more

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[gmlewis]

@Parker77 - do you have time for a code review?

[Parker77]

LGTM!

[gmlewis]

Thank you, @Parker77 !
Merging.