Update list of false positives for docs spell checking

Author: sadielbartholomew

docs/source/releases.rst

@@ -16,7 +16,7 @@ Documentation for all versions of cf.
 **CF-1.12**
 -----------
 
-* `Version 3.17.0 <https://ncas-cms.github.io/cf-python-docs/3.17.0>`_ (2025-03-24)
+* `Version 3.17.0 <https://ncas-cms.github.io/cf-python-docs/3.17.0>`_ (2025-04-02)
 
 **CF-1.11**
 -----------

docs/source/spelling_false_positives.txt

@@ -24,6 +24,7 @@ args
 asdata
 asdatetime
 asreftime
+astype
 atol
 ATOL
 attr
@@ -77,6 +78,7 @@ celsius
 centre
 centred
 cf
+cfdm
 CF
 cfa
 CFA
@@ -350,6 +352,7 @@ numblocks
 numpy
 onwards
 openmpi
+optimize
 optimize_graph
 orography
 orog