docs(optimistic-updates): ease wording in introduction

[BerniWittmann]

the introductionary text for optimistic update was in my opinion not easily understandable. Thus, i tried to improve the wording a little bit, to make it easier to grasp the objective.

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[BerniWittmann]

cc @alejo-monkee

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Codecov Report

Merging #2908 (75102f7) into master (c118513) will not change coverage.
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@@           Coverage Diff           @@
##           master    #2908   +/-   ##
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  Coverage   96.40%   96.40%           
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  Files          45       45           
  Lines        2226     2226           
  Branches      636      636           
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  Hits         2146     2146           
  Misses         77       77           
  Partials        3        3           

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[tannerlinsley]

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