docs: add Javadoc

src/main/java/com/github/polpetta/mezzotre/i18n/TemplateContentGenerator.java

@@ -8,7 +8,7 @@ import org.apache.velocity.VelocityContext;
 import org.apache.velocity.tools.ToolManager;
 import org.apache.velocity.util.StringBuilderWriter;
 
-// FIXME doc, tests
+// FIXME tests
 
 /**
  * This class aims to generate localized messages or strings either merging Velocity templates or
@@ -61,10 +61,27 @@ public class TemplateContentGenerator {
     return content.toString();
   }
 
+  /**
+   * Get a localized {@link String}
+   *
+   * @param locale a provided {@link Locale}
+   * @param key the key that will be retrieved from the localized messages
+   * @return a localized {@link String}
+   * @see #getString(String, String)
+   */
   public String getString(Locale locale, String key) {
     return localizedMessageFactory.createResourceBundle(locale).getString(key);
   }
 
+  /**
+   * Get a localized {@link String}
+   *
+   * @param localeAsString a provided {@link Locale} as a {@link String}. Will be converted using
+   *     {@link Locale#forLanguageTag(String)}
+   * @param key the key that will be retrieved from the localized messages
+   * @return a localized {@link String}
+   * @see #getString(Locale, String)
+   */
   public String getString(String localeAsString, String key) {
     return getString(Locale.forLanguageTag(localeAsString), key);
   }