[doc] Fix dead links checker

pmd-doc/pom.xml

@@ -24,6 +24,9 @@
                     <plugin>
                         <groupId>org.codehaus.mojo</groupId>
                         <artifactId>exec-maven-plugin</artifactId>
+                        <configuration>
+                            <classpathScope>test</classpathScope>
+                        </configuration>
                         <executions>
                             <execution>
                                 <id>generate-rule-docs</id>
@@ -97,6 +100,11 @@
             <artifactId>snakeyaml</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-simple</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>

pmd-doc/src/main/java/net/sourceforge/pmd/docs/DeadLinksChecker.java

@@ -276,6 +276,7 @@ public class DeadLinksChecker {
             while (captionMatcher.find()) {
                 final String anchor = captionMatcher.group(1)
                                                     .toLowerCase(Locale.ROOT)
+                                                    .replaceAll("'", "") // remove all apostrophes
                                                     .replaceAll("[^a-z0-9_]+", "-") // replace all non-alphanumeric characters with dashes
                                                     .replaceAll("^-+|-+$", ""); // trim leading or trailing dashes