Fix typo.

Doc/dist/dist.tex

@@ -1737,7 +1737,7 @@ The Python Package Index (PyPI) not only stores the package info, but also
 the package data if the author of the package wishes to. The distutils
 command \command{upload} pushes the distribution files to PyPI.
 
-The command is invokes immediately after building one or more distribution
+The command is invoked immediately after building one or more distribution
 files.  For example, the command
 
 \begin{verbatim}