codegen-java: Support not annotating constructor parameters (#792)

Motivation:
Spring Boot configuration classes neither require nor benefit from annotating constructor parameters with their name.
The same is true for pkl-config-java configuration classes compiled with `-parameter`.

Changes:
- Change CLI parameter `--params-annotation` to accept a `none` value.
  This is recommended in https://clig.dev/#arguments-and-flags and is how the `-F` parameter of the `ssh` command works.
- Change `paramsAnnotation` property in Gradle plugin, CliJavaCodeGeneratorOptions, and JavaCodegenOptions as follows:
  - Change meaning of `null` from "generate org.pkl.java.config.mapper.Named annotations" to "do not generate annotations".
    This is a breaking change (only) affecting users who explicitly set the property to `null` instead of omitting it.
  - Change property default from `null` to:
    `null` if `generateSpringBootConfig` is `true` and `org.pkl.java.config.mapper.Named` otherwise
- add tests
- update docs of this and other codegen options

Result:
Generated code does not contain unnecessary annotations.

pkl-codegen-kotlin/src/main/kotlin/org/pkl/codegen/kotlin/CliKotlinCodeGeneratorOptions.kt

@@ -29,13 +29,13 @@ data class CliKotlinCodeGeneratorOptions(
   /** The characters to use for indenting generated source code. */
   val indent: String = "  ",
 
-  /** Whether to generate Kdoc based on doc comments for Pkl modules, classes, and properties. */
+  /** Whether to preserve Pkl doc comments by generating corresponding KDoc comments. */
   val generateKdoc: Boolean = false,
 
   /** Whether to generate config classes for use with Spring Boot. */
   val generateSpringBootConfig: Boolean = false,
 
-  /** Whether to make generated classes implement [java.io.Serializable] */
+  /** Whether generated classes should implement [java.io.Serializable]. */
   val implementSerializable: Boolean = false,
 
   /**

pkl-codegen-kotlin/src/main/kotlin/org/pkl/codegen/kotlin/KotlinCodeGenerator.kt

@@ -32,13 +32,13 @@ data class KotlinCodeGeneratorOptions(
   /** The characters to use for indenting generated Kotlin code. */
   val indent: String = "  ",
 
-  /** Whether to generate KDoc based on doc comments for Pkl modules, classes, and properties. */
+  /** Whether to preserve Pkl doc comments by generating corresponding KDoc comments. */
   val generateKdoc: Boolean = false,
 
   /** Whether to generate config classes for use with Spring Boot. */
   val generateSpringBootConfig: Boolean = false,
 
-  /** Whether to make generated classes implement [java.io.Serializable] */
+  /** Whether to generate classes that implement [java.io.Serializable]. */
   val implementSerializable: Boolean = false,
 
   /**

pkl-codegen-kotlin/src/main/kotlin/org/pkl/codegen/kotlin/Main.kt

@@ -62,23 +62,21 @@ class PklKotlinCodegenCommand :
   private val generateKdoc: Boolean by
     option(
         names = arrayOf("--generate-kdoc"),
-        help =
-          "Whether to generate Kdoc based on doc comments " +
-            "for Pkl modules, classes, and properties."
+        help = "Whether to preserve Pkl doc comments by generating corresponding KDoc comments."
       )
       .flag()
 
   private val generateSpringboot: Boolean by
     option(
         names = arrayOf("--generate-spring-boot"),
-        help = "Whether to generate config classes for use with Spring boot."
+        help = "Whether to generate config classes for use with Spring Boot."
       )
       .flag()
 
   private val implementSerializable: Boolean by
     option(
         names = arrayOf("--implement-serializable"),
-        help = "Whether to make generated classes implement java.io.Serializable"
+        help = "Whether to generate classes that implement java.io.Serializable."
       )
       .flag()
 
@@ -90,7 +88,7 @@ class PklKotlinCodegenCommand :
           """
             Replace a prefix in the names of the generated Kotlin classes (repeatable).
             By default, the names of generated classes are derived from the Pkl module names.
-            With this option, you can override the modify the default names, renaming entire
+            With this option, you can override or modify the default names, renaming entire
             classes or just their packages.
           """
             .trimIndent()