Fix pre event check only checking start of flag

[0xAda]

Fixes #278

[codecov]

Codecov Report

Merging #283 (2838519) into master (94f3e97) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #283   +/-   ##
=======================================
  Coverage   96.87%   96.88%           
=======================================
  Files         111      111           
  Lines        5125     5141   +16     
  Branches      281      281           
=======================================
+ Hits         4965     4981   +16     
  Misses        128      128           
  Partials       32       32           

Impacted Files	Coverage Δ
src/plugins/flag/plaintext.py	100.00% <100.00%> (ø)
src/plugins/tests.py	100.00% <100.00%> (ø)

---

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 94f3e97...2838519. Read the comment docs.