More cleanup of older OTP versions (#15170)

* More cleanup since we require OTP 27

* Remove mentions to OTP25- in docs

* Use same versions in Getting Started as in Mix guide

Author: sabiwara

lib/elixir/lib/task/supervised.ex

@@ -122,8 +122,8 @@ defmodule Task.Supervised do
               function: fun,
               args: args,
               reason: {log_value(kind, value), __STACKTRACE__},
-              # TODO use Process.get_label/0 when we require Erlang/OTP 27+
-              process_label: Process.get(:"$process_label", :undefined)
+              # using :proc_lib over Process because we want the :undefined default, not nil
+              process_label: :proc_lib.get_label(self())
             }
           },
           %{

lib/elixir/pages/getting-started/introduction.md

@@ -15,8 +15,8 @@ Let's get started.
 
 If you haven't yet installed Elixir, visit our [installation page](https://elixir-lang.org/install.html). Once you are done, you can run `elixir --version` to get the current Elixir version. The requirements for this guide are:
 
-  * Elixir 1.15.0 onwards
-  * Erlang/OTP 26 onwards
+  * Elixir 1.18.0 onwards
+  * Erlang/OTP 27 onwards
 
 If you are looking for other resources for learning Elixir, you can also consult the [learning page](https://elixir-lang.org/learning.html) of the official website.
 

lib/iex/lib/iex.ex

@@ -29,7 +29,7 @@ defmodule IEx do
   aren't explicitly documented and where the function name is in the form
   of `__foo__`.
 
-  Autocomplete is available by default on Windows shells from Erlang/OTP 26.
+  Autocomplete is available by default on Windows shells.
 
   ## Encoding and coloring
 
@@ -41,14 +41,7 @@ defmodule IEx do
   PowerShell).
 
   Similarly, ANSI coloring is enabled by default on most Unix terminals.
-  They are also available on Windows consoles from Windows 10 and on
-  Erlang/OTP 26 or later. For earlier Erlang/OTP versions, you can
-  explicitly enable it for the current user in the registry by running
-  the following command:
-
-      $ reg add HKCU\Console /v VirtualTerminalLevel /t REG_DWORD /d 1
-
-  After running the command above, you must restart your current console.
+  They are also available on Windows consoles from Windows 10.
 
   ## Shell history
 

lib/mix/lib/mix/tasks/profile.tprof.ex

@@ -9,8 +9,6 @@ defmodule Mix.Tasks.Profile.Tprof do
   @moduledoc """
   Profiles the given file or expression using Erlang's `tprof` tool.
 
-  Requires Erlang/OTP27 or above.
-
   [`:tprof`](`:tprof`) is an experimental module introduced in Erlang/OTP 27 which
   provides a unified API for measuring call count, time, and allocation, and aims to
   replace [`:eprof`](`:eprof`) and [`:cprof`](`:cprof`).