Use typed throws in some methods that only raise a single error

Author: d-ronnqvist

Sources/SwiftDocC/Infrastructure/DocumentationContext.swift

@@ -2703,7 +2703,7 @@ public class DocumentationContext {
      - Returns: A ``DocumentationNode`` with the given identifier.
      - Throws: ``ContextError/notFound(_:)`` if a documentation node with the given identifier was not found.
      */
-    public func entity(with reference: ResolvedTopicReference) throws -> DocumentationNode {
+    public func entity(with reference: ResolvedTopicReference) throws(ContextError) -> DocumentationNode {
         if let cached = documentationCache[reference] {
             return cached
         }

Sources/SwiftDocC/Semantics/Symbol/Symbol.swift

@@ -461,14 +461,14 @@ extension Symbol {
     /// When building multi-platform documentation symbols might have more than one declaration
     /// depending on variances in their implementation across platforms (e.g. use `NSPoint` vs `CGPoint` parameter in a method).
     /// This method finds matching symbols between graphs and merges their declarations in case there are differences.
-    func mergeDeclaration(mergingDeclaration: SymbolGraph.Symbol.DeclarationFragments, identifier: String, symbolAvailability: SymbolGraph.Symbol.Availability?, alternateSymbols: SymbolGraph.Symbol.AlternateSymbols?, selector: UnifiedSymbolGraph.Selector) throws {
+    func mergeDeclaration(mergingDeclaration: SymbolGraph.Symbol.DeclarationFragments, identifier: String, symbolAvailability: SymbolGraph.Symbol.Availability?, alternateSymbols: SymbolGraph.Symbol.AlternateSymbols?, selector: UnifiedSymbolGraph.Selector) throws(DocumentationContext.ContextError) {
         let trait = DocumentationDataVariantsTrait(for: selector)
         let platformName = selector.platform
 
         func merge<Value: Equatable>(
             _ mergingValue: Value,
             into variants: inout DocumentationDataVariants<[[PlatformName?] : Value]>
-        ) throws {
+        ) throws(DocumentationContext.ContextError) {
             guard let platformName else {
                 variants[trait]?[[nil]] = mergingValue
                 return