Correct grammar, formatting and add download link (#3860)

Add a link to Godot Engine's download page.

getting_started/scripting/gdscript/gdscript_exports.rst

@@ -179,7 +179,7 @@ from the FileSystem dock at once.
 
     # Exported arrays can specify type (using the same hints as before).
 
-    export(Array, int) var ints = [1,2,3]
+    export(Array, int) var ints = [1, 2, 3]
     export(Array, int, "Red", "Green", "Blue") var enums = [2, 1, 0]
     export(Array, Array, float) var two_dimensional = [[1.0, 2.0], [3.0, 4.0]]
 

getting_started/scripting/gdscript/gdscript_styleguide.rst

@@ -640,7 +640,7 @@ Start with the ``_init()`` callback method, that the engine will call upon
 creating the object in memory. Follow with the ``_ready()`` callback, that Godot
 calls when it adds a node to the scene tree.
 
-These function should come first because they show how the object is
+These functions should come first because they show how the object is
 initialized.
 
 Other built-in virtual callbacks, like ``_unhandled_input()`` and

getting_started/scripting/gdscript/static_typing.rst

@@ -248,7 +248,7 @@ Typed or dynamic: stick to one style
 ------------------------------------
 
 Typed GDScript and dynamic GDScript can coexist in the same project. But
-I recommended to stick to either style for consistency in your codebase,
+I recommend to stick to either style for consistency in your codebase,
 and for your peers. It's easier for everyone to work together if you
 follow the same guidelines, and faster to read and understand other
 people's code.