Forward port changes from v0.6 release branch

Merge fixes and minor changes from release-0.6 branch, such as:
- Minor update to gen_tcp docs
- opcodesswitch: Fix LEDC.ex low_speed_mode()
- Update documentaion builds to OTP 28

Author: bettio

.github/workflows/build-docs.yaml

@@ -62,8 +62,7 @@ jobs:
         os: [ ubuntu-24.04 ]
     # The type of runner that the job will run on
     runs-on: ${{ matrix.os }}
-    # Documentation currently fails to build with OTP-27 and recent OTP-26.
-    container: erlang:26.0.2
+    container: erlang:28.1
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:

.github/workflows/publish-docs.yaml

@@ -49,7 +49,7 @@ jobs:
         os: [ ubuntu-24.04 ]
     # The type of runner that the job will run on
     runs-on: ${{ matrix.os }}
-    container: erlang:26.0.2
+    container: erlang:28.1
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:

libs/estdlib/src/gen_tcp.erl

@@ -31,7 +31,6 @@
 %% Caveats:
 %% <ul>
 %%     <li>Limited support for socket tuning parameters</li>
-%%     <li>No support for <b>controlling_process/2</b></li>
 %% </ul>
 %%
 %% <em><b>Note.</b>  Port drivers for this interface are not supported

libs/exavmlib/lib/LEDC.ex

@@ -344,18 +344,23 @@ defmodule LEDC do
     do: throw(:nif_error)
 
   @doc """
-  Convenience function for setting ledc speed mode
+  Convenience function for setting ledc speed mode, note that not all targets support high speed mode.
+  Function returns low speed mode on boards that do not support high speed mode.
   """
   @spec high_speed_mode() :: 0
   def high_speed_mode(),
     do: 0
 
   @doc """
-  Convenience function for setting ledc speed mode
-  """
-  @spec low_speed_mode() :: 1
-  def low_speed_mode(),
-    do: 1
+  Convenience function for setting ledc low speed mode.
+  """
+  @spec low_speed_mode() :: 0 | 1
+  def low_speed_mode() do
+    case :erlang.system_info(:esp32_chip_info) do
+      %{model: :esp32} -> 1
+      _ -> 0
+    end
+  end
 
   @doc """
   Convenience function for setting ledc fade mode