Missing semi-colon in 'interest-is-interesting' tutorial added

[shankarlohar]

fixes #732

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[vaeng]

You need to fix this in 3 places:

• cpp/concepts/loops/about.md

  Line 60 in a7653bb

  int sum{0}

• cpp/concepts/loops/introduction.md

  Line 60 in a7653bb

  int sum{0}

• cpp/exercises/concept/interest-is-interesting/.docs/introduction.md

  Line 60 in a7653bb

  int sum{0}

[shankarlohar]

okay

[shankarlohar]

Done! @vaeng

[vaeng]

I did a merge and pushed to retrigger the actions, somehow they got lost and did not report back, so your PR could not be merged