I just installed qtcreator and noticed that it lists qt5-docs as an optional depend but it doesn't exist in the repo. It needs to be changed to qt5-doc.
Optional dependencies for qtcreator
qt5-docs: for the integrated Qt documentation
gdb: for the debugger [installed]
cmake: for cmake project suppport
git: for git support [installed]
mercurial: for mercurial support
bzr: for bazaar support