Update docs/sphinx/source/whatsnew/v0.13.1.rst

Co-authored-by: RDaxini <143435106+RDaxini@users.noreply.github.com>

Author: kandersolar

docs/sphinx/source/whatsnew/v0.13.1.rst

@@ -20,6 +20,7 @@ Bug fixes
 Enhancements
 ~~~~~~~~~~~~
 * :py:func:`pvlib.spectrum.spectral_factor_firstsolar` no longer emits warnings
+
   when airmass and precipitable water values fall out of range. (:pull:`2512`)
 
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