fix description for unknown-preprocessor-directives

README.md

@@ -596,6 +596,8 @@ Checks if the same modifier is used multiple times in a single network rule.
 
 Checks if the used preprocessor directives are known.
 
+> **Note**: Preprocessor directives are case-sensitive, so `!#IF` is to be considered as invalid.
+
 - **Severity:** `error` (2)
 - **Options:** none
 - **Fixable:** no
@@ -611,6 +613,7 @@ Checks if the used preprocessor directives are known.
 - **Additional information:**
     - Currently, the following preprocessor directives are supported:
         - `if`: [reference][if-kb]
+        - `else`: [reference][if-kb]
         - `endif`: [reference][if-kb]
         - `include`: [reference][include-kb]
         - `safari_cb_affinity`: [reference][safari-cb-kb]

src/linter/rules/unknown-preprocessor-directives.ts

@@ -15,7 +15,9 @@ function isKnownPreProcessorDirective(name: string): boolean {
 }
 
 /**
- * Rule that checks if a preprocessor directive is known
+ * Rule that checks if a preprocessor directive is known.
+ *
+ * Directives are case-sensitive, so `!#IF` is to be considered as invalid.
  */
 export const UnknownPreProcessorDirectives: LinterRule = {
     meta: {