Adds missing @NotNull annotations

src/main/java/net/knarcraft/knarlib/formatting/StringReplacer.java

@@ -1,5 +1,7 @@
 package net.knarcraft.knarlib.formatting;
 
+import org.jetbrains.annotations.NotNull;
+
 import java.util.HashMap;
 import java.util.Map;
 
@@ -25,7 +27,7 @@ public final class StringReplacer {
      *
      * @param replacementInput <p>The input string to replace placeholders for</p>
      */
-    public StringReplacer(String replacementInput) {
+    public StringReplacer(@NotNull String replacementInput) {
         this.replacementInput = replacementInput;
     }
 
@@ -35,7 +37,7 @@ public final class StringReplacer {
      * @param placeholder <p>The placeholder to replace</p>
      * @param value       <p>The replacement value</p>
      */
-    public void add(String placeholder, String value) {
+    public void add(@NotNull String placeholder, @NotNull String value) {
         this.replacements.put(placeholder, value);
     }
 
@@ -44,7 +46,7 @@ public final class StringReplacer {
      *
      * @param placeholder <p>The placeholder to remove</p>
      */
-    public void remove(String placeholder) {
+    public void remove(@NotNull String placeholder) {
         this.replacements.remove(placeholder);
     }
 
@@ -55,7 +57,7 @@ public final class StringReplacer {
      *
      * @return <p>The string with placeholders replaced</p>
      */
-    public String replace() {
+    public @NotNull String replace() {
         if (replacementInput == null) {
             throw new IllegalStateException("This method cannot be run without a defined string");
         }
@@ -68,7 +70,7 @@ public final class StringReplacer {
      * @param input <p>The string to replace placeholders in</p>
      * @return <p>The string with placeholders replaced</p>
      */
-    public String replace(String input) {
+    public @NotNull String replace(@NotNull String input) {
         return StringFormatter.replacePlaceholders(input, replacements.keySet().toArray(new String[0]),
                 replacements.values().toArray(new String[0]));
     }