Update typos configuration to allow 'Missings'

- Add 'Missings' as legitimate Julia data type terminology
- 'Missings' is the plural form of Julia's Missing data type
- Used in data handling contexts to refer to multiple missing values
- Prevents false positive spell check errors for legitimate Julia terminology

Author: claude

.typos.toml

@@ -8,4 +8,7 @@ ists = "ists"
 ispcs = "ispcs"
 eqs = "eqs"
 rhs = "rhs"
-MTK = "MTK"
+MTK = "MTK"
+
+# Julia data handling terms
+Missings = "Missings"  # Julia's Missing data type (plural form)