Update deprecation messages to give the API a full minor release before being removed (#1310)

Author: d-ronnqvist

Sources/SwiftDocC/Checker/Checkers/AbstractContainsFormattedTextOnly.swift

@@ -14,7 +14,7 @@ public import Markdown
 /**
  A document's abstract may only contain formatted text. Images and links are not allowed.
  */
-@available(*, deprecated, message: "This check is no longer applicable. This deprecated API will be removed after 6.3 is released")
+@available(*, deprecated, message: "This check is no longer applicable. This deprecated API will be removed after 6.4 is released")
 public struct AbstractContainsFormattedTextOnly: Checker {
     public var problems: [Problem] = [Problem]()
     private var sourceFile: URL?

Sources/SwiftDocC/LinkTargets/LinkDestinationSummary.swift

@@ -226,7 +226,7 @@ public struct LinkDestinationSummary: Codable, Equatable {
         /// If the summarized element has a declaration but the variant doesn't, this property will be `Optional.some(nil)`.
         public let subheadingDeclarationFragments: VariantValue<DeclarationFragments?>
 
-        @available(*, deprecated, renamed: "subheadingDeclarationFragments", message: "Use 'subheadingDeclarationFragments' instead. This deprecated API will be removed after 6.3 is released.")
+        @available(*, deprecated, renamed: "subheadingDeclarationFragments", message: "Use 'subheadingDeclarationFragments' instead. This deprecated API will be removed after 6.4 is released.")
         public var declarationFragments: VariantValue<DeclarationFragments?> {
             subheadingDeclarationFragments
         }
@@ -241,7 +241,7 @@ public struct LinkDestinationSummary: Codable, Equatable {
         /// Images that are used to represent the summarized element or `nil` if the images are the same as the summarized element.
         ///
         /// If the summarized element has an image but the variant doesn't, this property will be `Optional.some(nil)`.
-        @available(*, deprecated, message: "`TopicRenderReference` doesn't support variant specific topic images. This property will be removed after 6.3 is released")
+        @available(*, deprecated, message: "`TopicRenderReference` doesn't support variant specific topic images. This property will be removed after 6.4 is released")
         public let topicImages: VariantValue<[TopicImage]?> = nil
 
         /// Creates a new summary variant with the values that are different from the main summarized values.
@@ -284,7 +284,7 @@ public struct LinkDestinationSummary: Codable, Equatable {
             self.navigatorDeclarationFragments = navigatorDeclarationFragments
         }
 
-        @available(*, deprecated, renamed: "init(traits:kind:language:relativePresentationURL:title:abstract:taskGroups:usr:plainTextDeclaration:subheadingDeclarationFragments:navigatorDeclarationFragments:)", message: "Use `init(traits:kind:language:relativePresentationURL:title:abstract:taskGroups:usr:plainTextDeclaration:subheadingDeclarationFragments:navigatorDeclarationFragments:)` instead. `TopicRenderReference` doesn't support variant specific topic images. This property will be removed after 6.3 is released")
+        @available(*, deprecated, renamed: "init(traits:kind:language:relativePresentationURL:title:abstract:taskGroups:usr:plainTextDeclaration:subheadingDeclarationFragments:navigatorDeclarationFragments:)", message: "Use `init(traits:kind:language:relativePresentationURL:title:abstract:taskGroups:usr:plainTextDeclaration:subheadingDeclarationFragments:navigatorDeclarationFragments:)` instead. `TopicRenderReference` doesn't support variant specific topic images. This property will be removed after 6.4 is released")
         public init(
             traits: [RenderNode.Variant.Trait],
             kind: VariantValue<DocumentationNode.Kind> = nil,
@@ -375,7 +375,7 @@ public struct LinkDestinationSummary: Codable, Equatable {
         self.variants = variants
     }
 
-    @available(*, deprecated, renamed: "init(kind:language:relativePresentationURL:referenceURL:title:abstract:availableLanguages:platforms:taskGroups:usr:plainTextDeclaration:subheadingDeclarationFragments:navigatorDeclarationFragments:redirects:topicImages:references:variants:)", message: "Use `init(kind:language:relativePresentationURL:referenceURL:title:abstract:availableLanguages:platforms:taskGroups:usr:plainTextDeclaration:subheadingDeclarationFragments:navigatorDeclarationFragments:redirects:topicImages:references:variants:)` instead. This property will be removed after 6.3 is released")
+    @available(*, deprecated, renamed: "init(kind:language:relativePresentationURL:referenceURL:title:abstract:availableLanguages:platforms:taskGroups:usr:plainTextDeclaration:subheadingDeclarationFragments:navigatorDeclarationFragments:redirects:topicImages:references:variants:)", message: "Use `init(kind:language:relativePresentationURL:referenceURL:title:abstract:availableLanguages:platforms:taskGroups:usr:plainTextDeclaration:subheadingDeclarationFragments:navigatorDeclarationFragments:redirects:topicImages:references:variants:)` instead. This property will be removed after 6.4 is released")
     public init(
         kind: DocumentationNode.Kind,
         language: SourceLanguage,