refactor: Don't use static set for matchedPatterns

The matchedPatterns are only relevant for the current lint run and
should not be stored in a static set that won't be cleared between
multiple lint runs in the same process. There doesn't seem to be a need
to have the set statically available.

src/linter/linter.ts

@@ -11,11 +11,6 @@ import type {AbstractReader, Resource} from "@ui5/fs";
 import ConfigManager, {UI5LintConfigType} from "../utils/ConfigManager.js";
 import {Minimatch} from "minimatch";
 
-// Internal analytical variable that will store matchers' count.
-// We cannot predict the outcome of the matchers, so stash usage statistics
-// and later analyze the results from it.
-const matchedPatterns = new Set<string>();
-
 export async function lintProject({
 	rootDir, filePatterns, ignorePattern, reportCoverage, includeMessageDetails, configPath, ui5ConfigPath,
 }: LinterOptions): Promise<LintResult[]> {
@@ -128,6 +123,11 @@ async function lint(
 	// Resolve files to include
 	filePatterns = filePatterns ?? config.files ?? [];
 
+	// We cannot predict the outcome of the matchers, so we remember the used patterns
+	// and later compare them against the provided filePatterns to find patterns
+	// that didn't match any file
+	const matchedPatterns = new Set<string>();
+
 	// Resolve ignores
 	ignorePattern = [
 		...(config.ignores ?? []),