kondo cleaning and additional tests for the slack adapter

[gkspranger]

• src/yetibot/core/adapters/slack.clj
  • many recommendations made by clj-kondo to drop unused libs, refs, and bindings
  • added some docstrings
  • performed integration test using new core binary and did not see any wild errors when joining channel, leaving channel, sending messages, etc
  • simplecov may yell at me because i made changes in functions that have no tests
• test/yetibot/core/test/adapters/slack.clj
  • added a couple of tests

[codecov[bot]]

Codecov Report

Merging #194 (4644d47) into master (5220bdc) will increase coverage by 0.26%. The diff coverage is 94.11%.

@@            Coverage Diff             @@
##           master     #194      +/-   ##
==========================================
+ Coverage   56.47%   56.74%   +0.26%     
==========================================
  Files          94       94              
  Lines        4131     4131              
  Branches      221      222       +1     
==========================================
+ Hits         2333     2344      +11     
+ Misses       1577     1565      -12     
- Partials      221      222       +1     

Impacted Files	Coverage Δ
src/yetibot/core/adapters/slack.clj	52.17% <94.11%> (+3.18%)	:arrow_up:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 5220bdc...4644d47. Read the comment docs.