Update list-form-conditional-show-hide.md

Updated the conditional 'Show Hide' for Form customisation in lists with 2 further valid formula for Boolean (Yes/No) columns.

Author: influential-eliot

docs/declarative-customization/list-form-conditional-show-hide.md

@@ -132,6 +132,16 @@ The following formula checks if the Yes/No column `[$Promoted]` is equal to a Ye
 =if([$Promoted] == true, 'true', 'false')
 ```
 
+The following are also valid:
+
+```
+=if([$Promoted], 'true', 'false')
+```
+
+```
+=[$Promoted]
+```
+
 ##### Lookup column
 
 > [!NOTE]