docs: remove RTD download PDF links

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docs/en/index.rst

@@ -58,8 +58,7 @@ This is the documentation for Espressif IoT Development Framework (`esp-idf <htt
    Copyrights <COPYRIGHT>
    About <about>
    语言/Languages <languages>
-   Guide Downloads <https://readthedocs.com/projects/espressif-esp-idf/downloads/>
-   
+
 * :ref:`genindex`
 
 

docs/zh_CN/index.rst

@@ -61,7 +61,6 @@ ESP-IDF 是 `ESP32 <https://www.espressif.com/zh-hans/products/hardware/esp32/ov
    版权 <COPYRIGHT>
    关于 <about>
    Languages/语言 <languages>
-   指南下载 <https://readthedocs.com/projects/espressif-esp-idf/downloads/>
 
 
 * :ref:`genindex`