Fixed typos/spelling errors in scenarios/speed

Author: rgbkrk

docs/scenarios/speed.rst

@@ -42,7 +42,7 @@ The GIL
 
 `The GIL`_ (Global Interpreter Lock) is how Python allows multiple threads to
 operate at the same time. Python's memory management isn't entirely thread-safe,
-so the GIL is required to prevents multiple threads from running the same
+so the GIL is required to prevent multiple threads from running the same
 Python code at once.
 
 David Beazley has a great `guide`_ on how the GIL operates. He also covers the
@@ -58,8 +58,8 @@ C Extensions
 The GIL
 -------
 
-`Special care`_ must be taken when writing C extensions to make sure you r
-egister your threads with the interpreter.
+`Special care`_ must be taken when writing C extensions to make sure you
+register your threads with the interpreter.
 
 C Extensions
 ::::::::::::
@@ -86,7 +86,7 @@ Threading
 ---------
 
 
-Spanwing Processes
+Spawning Processes
 ------------------