Fix win command for downloading bisect-builds.py

The command was a modified version of the command in the original docs
which works with Python 3 (instead of Python 2). Unfortunately, there
were 2 bugs with that command:

- The bytes were not decoded to UTF-8 before printing, and so the output
  was malformed.
- By default PowerShell doesn't write files in UTF-8 encoding, so the
  written file couldn't be interpreted by Python.

These issues are fixed in the updated command.

Change-Id: I0035f902c37317af2e98e213fae3c10254f5cf34
diff --git a/docs/chrome/desarrolladores/biseccion.md b/docs/chrome/desarrolladores/biseccion.md
index 696e81b..e5253cb 100644
--- a/docs/chrome/desarrolladores/biseccion.md
+++ b/docs/chrome/desarrolladores/biseccion.md
@@ -51,7 +51,7 @@
     6. En la ventana que aparece, copia y pega el siguiente comando usando la
     combinación de teclas ++ctrl+v++ y pulsa ++enter++ para ejecutarlo:
     ```
-    python -c "import urllib.request; import base64; print(base64.b64decode(urllib.request.urlopen('https://chromium.googlesource.com/chromium/src/+/master/tools/bisect-builds.py?format=text').read())" > bisect-builds.py
+    python -c "import urllib.request; import base64; print(base64.b64decode(urllib.request.urlopen('https://chromium.googlesource.com/chromium/src/+/master/tools/bisect-builds.py?format=text').read()).decode())" | Out-File -FilePath bisect-builds.py -Encoding utf8
     ```
     <div style="text-align: center;"><a href="../../../img/bisect_tool_install_win.png" target="_blank" rel="noopener nofollow"><img src="../../../img/bisect_tool_install_win.png" style="max-width: 350px;"></a><br><span style="color: gray;">[haz clic encima de las imágenes para hacerlas más grandes]</span></div>