* maint-20:
  Updated OTP version
  Update release notes
  Update version numbers
  erts: Add system_flags(erts_alloc,"+M?sbct *")
  erts: Add age order first fit allocator strategies
  erts: Refactor erl_ao_firstfit_alloc
  erts: Add migration options "acnl" and "acfml"
  kernel: Add os:cmd/2 with max_size option
  erts: Add more stats for mbcs_pool
  erts: Fix alloc_SUITE:migration
  stdlib: Make ets_SUITE memory check try again
  erts: Improve carrier pool search
  erts: Improve alloc_SUITE:migration
  erts: Refactor carrier dealloc migration

The Design Principles states that an application can have Erlang
source files one level below the "src" directory, and now
filelib:find_source() by default searches one level below "src".

The same applies to "esrc". That directory is only mentioned in
filename(3).

* lukas/system/improve_profile_docs/OTP-14633:
  erts: Add term2bin note about encoding guarantee
  Fix broken link in INSTALL howto
  system: Add info to profiling effeciency guide
  Update message queue and pinfo binary docs
  kernel: Clarify gen_tcp:listen documentation
  system: Add External OSS tools section to profiling guilde

This commit also adds a check to see that all files that
are part of an xi:include also have part of XML_FILES
and vice versa. It also fixes any applications where this
was not true.

This reverts commit 0717a2194e863f3a78595184ccc5637697f03353, reversing
changes made to 71a40658a0cef8b3e25df3a8e48a72d0563a89bf.