docs: Remove trailing spaces and convert tabs to spaces.

Signed-off-by: Damien George <damien@micropython.org>

docs/develop/extendingmicropython.rst

@@ -16,4 +16,3 @@ live in the main MicroPython repository.
 
    cmodules.rst
    natmod.rst
-   

docs/develop/gettingstarted.rst

@@ -60,10 +60,10 @@ After the above configuration, your setup should be similar to this:
 .. code-block:: bash
 
    $ git remote -v
-   origin	https://github.com/<your-user-name>/micropython (fetch)
-   origin	https://github.com/<your-user-name>/micropython (push)
-   upstream	https://github.com/micropython/micropython (fetch)
-   upstream	https://github.com/micropython/micropython (push)
+   origin       https://github.com/<your-user-name>/micropython (fetch)
+   origin       https://github.com/<your-user-name>/micropython (push)
+   upstream     https://github.com/micropython/micropython (fetch)
+   upstream     https://github.com/micropython/micropython (push)
 
 You should now have a copy of the source code. By default, you are pointing
 to the master branch. To prepare for further development, it is recommended
@@ -140,8 +140,8 @@ If it built successfully, you should see a message similar to this:
 .. code-block:: bash
 
    LINK mpy-cross
-      text	   data	    bss	    dec	    hex	filename
-    279328	    776	    880	 280984	  44998	mpy-cross
+      text          data    bss     dec     hex filename
+    279328          776     880  280984   44998 mpy-cross
 
 .. note::
 
@@ -181,8 +181,8 @@ If MicroPython built correctly, you should see the following:
 .. code-block:: bash
 
    LINK micropython
-      text	   data	    bss	    dec	    hex	filename
-    412033	   5680	   2496	 420209	  66971	micropython
+      text         data     bss     dec     hex filename
+    412033         5680    2496  420209   66971 micropython
 
 Now run it:
 

docs/develop/index.rst

@@ -24,4 +24,3 @@ MicroPython to a new platform and implementing a core MicroPython library.
    publiccapi.rst
    extendingmicropython.rst
    porting.rst
-