[crystax] Text corrections for doc files

- Fix misspelled word
- update docker image size to the current situation

Thanks @AndreMiras!!

Author: opacam

doc/source/buildoptions.rst

@@ -43,7 +43,7 @@ recipe.
 .. note:: Since we don't support `python3crystax` anymore, the old instructions
           has been removed from here. If you, still have the need to make use
           of this old recipe, you should do it with an old `python-for-android`
-          release. Probably, a got starting point would be `version 0.7.0
+          release. Probably, a good starting point would be `version 0.7.0
           <https://github.com/kivy/python-for-android/archive/0.7.0.zip>`__ or
           if that doesn't work , then go for `version 0.6.0
           <https://github.com/kivy/python-for-android/archive/0.6.0.zip>`__

doc/source/docker.rst

@@ -21,7 +21,7 @@ already have Docker preinstalled and set up.
    Within the custom diff made by building the distribution there is another
    big chunk of space eaten. The very basic stuff such as a distribution with:
    CPython 3, setuptools, Python for Android ``android`` module, SDL2 (+ deps),
-   PyJNIus and Kivy takes almost 13 GB. Check your free space first!
+   PyJNIus and Kivy takes almost 2 GB. Check your free space first!
 
 1. Clone the repository::