Fix typos in docs and docstrings (GH-13745)

diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst
index 15e707a..2a3ffb5 100644
--- a/Doc/library/dis.rst
+++ b/Doc/library/dis.rst
@@ -708,7 +708,7 @@
 
    Cleans up the value stack and the block stack.  If *preserve_tos* is not
    ``0`` TOS first is popped from the stack and pushed on the stack after
-   perfoming other stack operations:
+   performing other stack operations:
 
    * If TOS is ``NULL`` or an integer (pushed by :opcode:`BEGIN_FINALLY`
      or :opcode:`CALL_FINALLY`) it is popped from the stack.