Explain the rationale for formatting rule choices in comments (#25)

src/immaculate/groovy/net/neoforged/gradleutils/immaculate/ImmaculateConfiguration.groovy

@@ -39,16 +39,26 @@ final class ImmaculateConfiguration {
 
     static void configure(FormattingWorkflow workflow, File configPath) {
         workflow.java()
+        // Ending files by a new line is good practice, and avoids "No newline at end of file" comments by Git.
         workflow.trailingNewline()
+        // Tabs can render differently, and can accidentally be inserted. Enforce spaces only.
         workflow.noTabs()
+        // Reorder imports according to simple lexicographic ordering, and remove unused imports.
         workflow.googleFixImports()
+        // Allow disabling the formatter for specific sections. Should be used sparingly.
         workflow.toggleOff.set('spotless:off')
         workflow.toggleOn.set('spotless:on')
+        // Most formatting rules are handled by the eclipse formatter config.
+        // They are generally chosen to match standard Java style, and eliminate discussions about style.
         workflow.eclipse {
             it.version '3.37.0'
             it.config.set(configPath)
         }
 
+        // Wildcard imports:
+        // - cannot be automatically removed if unused
+        // - make it harder to see which classes are being used
+        // - are often inserted automatically by IDEs, which leads to unnecessary diffs in imports
         // courtesy of diffplug/spotless#240
         // https://github.com/diffplug/spotless/issues/240#issuecomment-385206606
         workflow.custom 'noWildcardImports', { String fileContents ->
@@ -57,12 +67,18 @@ final class ImmaculateConfiguration {
             }
         }
 
+        // Mixing non-nullable annotations with non-annotated types leads to confusion
+        // wrt. nullability of non-annotated types.
+        // Annotating all types would be too verbose, so we assume non-nullability by default,
+        // and disallow non-null annotations which are then unnecessary.
         workflow.custom 'noNotNull', { String fileContents ->
             if (fileContents.contains('@NotNull') || fileContents.contains('@Nonnull')) {
                 throw new InvalidUserDataException('@NotNull and @Nonnull are disallowed.')
             }
         }
 
+        // JetBrains nullability annotations can be used in more contexts,
+        // and we also use other JB annotations such as @ApiStatus.
         workflow.custom 'jetbrainsNullable', { String fileContents ->
             fileContents.replace('javax.annotation.Nullable', 'org.jetbrains.annotations.Nullable')
         }