Add FAQ to PlatformIO IDE and auto save modified files on build

docs/faq.rst

@@ -59,6 +59,11 @@ To enable ``zsh`` completion please run these commands:
     For permanent command completion you need to place commands above to
     ``~/.bashrc`` or ``~/.zshrc`` file.
 
+PlatformIO IDE
+--------------
+
+Please refer to :ref:`PlatformIO IDE Frequently Asked Questions <ide_atom_faq>`.
+
 .. _faq_troubleshooting:
 
 Troubleshooting
@@ -89,8 +94,7 @@ Where is ``platformio`` binary installed? Run this command in Terminal
     # for Unix
     which platformio
     echo $PATH
-
+ Windows OS
-    # for Windows OS
     where platformio
     echo %PATH%
 

docs/ide/atom.rst

@@ -432,6 +432,17 @@ To force Smart Code Linter to use Arduino files as C++ please
 2. Perform all steps from :ref:`ide_atom_knownissues_sclarduino_manually`
    (without renaming to ``.cpp``).
 
+.. _ide_atom_faq:
+
+Frequently Asked Questions
+--------------------------
+
+Automatically save on build
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+If you want automatically save all edited files when triggering a build, please follow to
+``Menu: PlatformIO > Settings > Build`` and check ``Automatically save on build``.
+
 Articles / Manuals
 ------------------