added label `SIZE_AUTO` for better readability if a size in a `ImVec` is zero for automatic sizing.

3 jobs for develop in 13 minutes and 30 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Build
passed build-clang #7773

00:03:07

passed build-gcc #7772

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passed build-scanbuild #7774

00:06:38