[readme.md] remove incorrect self argument from page action callback

[pawelmhm]

minor documentation fix, thanks for actions btw @elacuesta , they look really useful, testing them now

[codecov]

Codecov Report

Merging #35 (e404d0f) into master (190b3f3) will not change coverage.
The diff coverage is n/a.

❗ Current head e404d0f differs from pull request most recent head 9f30295. Consider uploading reports for the commit 9f30295 to get more accurate results

@@            Coverage Diff            @@
##            master       #35   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            3         3           
  Lines          168       168           
=========================================
  Hits           168       168           

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