[refactor] Address 4 low-risk Codacy findings on this PR

Quick wins picked from the Codacy report — small, mechanical cleanups
that do not touch any of the pre-existing NPath complexity territory
that @line-o flagged as a conflict-with-other-PRs risk.

- FunUnparsedText.java: replace fully-qualified StandardCharsets.UTF_8
  with the already-static-imported UTF_8 (UnnecessaryFullyQualifiedName)
- FunMatches.java: collapse a nested if into a single condition
  (CollapsibleIfStatements)
- XQueryContext.ModuleVertex.equals: combine the two-step namespace +
  location comparison into a single && return (SimplifyBooleanReturns)
- RegexUtil.java: remove unused convertUnicodeBlockNames(String) private
  method (UnusedPrivateMethod) -- left over from an early Java-regex
  implementation attempt before the validation path moved to Saxon

The remaining 10 NPath complexity warnings and the AvoidReassigningParameters
warnings are left untouched per @line-o's note about pre-existing complexity
raising conflict risk with other PRs in the pipeline.

Verified: build clean, XQuery3Tests 1026/1026 pass.

Author: joewiz

exist-core/src/main/java/org/exist/xquery/XQueryContext.java

@@ -3874,10 +3874,7 @@ public boolean equals(final Object o) {
             }
 
             final ModuleVertex that = (ModuleVertex) o;
-            if (!namespaceURI.equals(that.namespaceURI)) {
-                return false;
-            }
-            return location.equals(that.location);
+            return namespaceURI.equals(that.namespaceURI) && location.equals(that.location);
         }
 
         @Override

exist-core/src/main/java/org/exist/xquery/functions/fn/FunMatches.java

@@ -440,13 +440,10 @@ private Sequence evalWithIndex(final Sequence contextSequence, final Item contex
                     // restricted to that QName
                     contextQName = null;
                 }
-                if (!indexFound && contextQName == null) {
-                    // if there are some indexes defined on a qname,
-                    // we need to check them all
-                    if (iflags.hasIndexOnQNames()) {
-                        indexScan = true;
-                    }
-                    // else use range index defined on path by default
+                // if there are some indexes defined on a qname, we need to check them all;
+                // otherwise use range index defined on path by default
+                if (!indexFound && contextQName == null && iflags.hasIndexOnQNames()) {
+                    indexScan = true;
                 }
             } else {
                 result = evalFallback(nodes, pattern, flags, indexType);

exist-core/src/main/java/org/exist/xquery/functions/fn/FunUnparsedText.java

@@ -320,7 +320,7 @@ private Charset getCharset(final String encoding, final Source source) throws XP
                 throw new XPathException(this, ErrorCodes.FOUT1170, e.getMessage());
             }
             if (charset == null) {
-                charset = StandardCharsets.UTF_8;
+                charset = UTF_8;
             }
         } else {
             try {

exist-core/src/main/java/org/exist/xquery/regex/RegexUtil.java

@@ -160,16 +160,6 @@ public static String translateRegexp(final Expression context, final String patt
         }
     }
 
-    /**
-     * Convert XML Schema/XPath \p{Is<Block>} and \P{Is<Block>} Unicode block
-     * property escapes to Java's \p{In<Block>} and \P{In<Block>} syntax.
-     */
-    private static String convertUnicodeBlockNames(final String pattern) {
-        return pattern
-                .replaceAll("\\\\p\\{Is([^}]+)}", "\\\\p{In$1}")
-                .replaceAll("\\\\P\\{Is([^}]+)}", "\\\\P{In$1}");
-    }
-
     /**
      * Validates that a regex pattern only uses constructs allowed by the XPath
      * regular expression specification (F&amp;O 3.1, Section 5.6.1), with