Added return type to Stopwatch::getSections()
minor #11067 [Stopwatch] Added return type to Stopwatch::getSections() (umpirsky)

This PR was merged into the 2.6-dev branch.

Discussion
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[Stopwatch] Added return type to Stopwatch::getSections()

https://github.com/symfony/symfony/pull/10851#discussion_r13479016

Commits
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ab00361 Added return type to Stopwatch::getSections()
[Debug] simplify code path to remove potential blank pages
[Debug] generalized ErrorHandler
[Debug] update FrameworkBundle and HttpKernel for new ErrorHandler