DOC: optimize: fix a typo in nnls documentation (scipy#24061)

Author: kleiter

scipy/optimize/_nnls.py

@@ -44,7 +44,7 @@ def nnls(A, b, *, maxiter=None, atol=_NoValue):
     Notes
     -----
     The code is based on the classical algorithm of [1]_. It utilizes an active
-    set method and solves the KKK (Karush-Kuhn-Tucker) conditions for the
+    set method and solves the KKT (Karush-Kuhn-Tucker) conditions for the
     non-negative least squares problem.
 
     References