Bugfix: fix link to wikipedia vector graphics page (#1031)

Author: anooprh

docs/source/tutorials/building_blocks.rst

@@ -36,7 +36,7 @@ to use plain instances of :class:`.Mobject`; instead you will most likely
 create instances of its derived classes.  One of these derived classes is
 :class:`.VMobject`.  The ``V`` stands for Vectorized Mobject.  In essence, a
 vmobject is a mobject that uses vector `vector graphics
-<https://en.wikipedia.org/wiki/Vector_graphics/>`_ to be displayed.  Most of
+<https://en.wikipedia.org/wiki/Vector_graphics>`_ to be displayed.  Most of
 the time, you will be dealing with vmobjects, though we will continue to use
 the term "mobject" to refer to the class of shapes that can be displayed on
 screen, as it is more general.