fix: improper enforcement of natspec rule on internals

Author: dbale-altoros

docs/rules/best-practices/use-natspec.md

@@ -57,6 +57,8 @@ This rule accepts an array of options:
 ```
 
 ### Notes
+- For `internal` or `private` function this rule checks natspec as configured, only if there are tags present. If not, function is skipped.
+- For `external` or `public` function this rule checks natspec as specified in the config.
 - If a function or return value has unnamed parameters (e.g. `function foo(uint256)`), the rule only checks the number of `@param` or `@return` tags, not their names.
 - If a function or variable has `@inheritdoc`, the rule skips the validation.
 - The rule supports both `///` and `/** */` style NatSpec comments.