inets httpc: Corrected separation of pipelining and persisten connections

OTP-10845
inets httpd: The option modules now defaults to its documented default value.

OTP-10844
filelib: Update documentation
file: Remove note about Unicode handling being experimental
file: Document list_dir_all/1 and read_link_all/1
Fix some Unicode issues

Also let the Erlang shell use the new function io:printable_range().
Add +pc {latin1|unicode} switch and io:printable_range/0

This is the base for implementing configurable
~tp printouts, so that the user can define which
characters to view as actually printable in the shell and
by io_lib:format.

The functionality is neither documented nor used in this commit
Add usage of and spec for io:printable_range/0

This makes both io:format("~tp", ...) and
the shell honor the +pc setting and also reverts the shell to
the old behaviour of only interpreting latin1 strings as "strings"
by default. +pc unicode turns on the R16A behaviour. Doing
io:format("~tp~n", [[1024,1025]]).
will show you the difference when starting with +pc unicode.
Document +pc flag and io:printable_range/0
Make printing of UTF-8 in binaries behave like lists.

This means that only UTF-8 characters in binaries that conform
to the printable_range are printed as <<"..."/utf8>> in io_lib_pretty.
Add testcase for +pc and io:printable_range/0

Also fixed otp_10302 to test both on a node with +pc unicode and
a node with +pc latin1.
Fix io_proto_SUITE to handle the new io_lib_pretty:print
Make shell_SUITE:otp_10302 use +pc unicode when needed
Merge branch 'hb/stdlib/unicode_corrections/OTP-10820' into pan/unicode_printable_ranges

* hb/stdlib/unicode_corrections/OTP-10820:
  Fix some Unicode issues

Conflicts:
	lib/stdlib/test/shell_SUITE.erl
Remove newly introduced warning in erlexec.c
Leave the +pc handling to io and io_lib_pretty

This makes the shell output binaries and list as intended by
the +pc setting.
Make ~tp output latin1 binaries as strings if possible
Correct misspelled comments and space at lin ends
Make wx debugger use +pc flag when applicable
Update primary bootstrap