[SwiftExtract] Record the source file path on ExtractedFunc

Sources/SwiftExtract/ExtractedDecls.swift

@@ -309,6 +309,10 @@ public final class ExtractedFunc: ExtractedSwiftDecl, CustomStringConvertible {
 
   public let functionSignature: SwiftFunctionSignature
 
+  // The short path from module root to the file in which this declaration was originally declared.
+  // E.g. for `Sources/Example/My/Types.swift` it would be `My/Types.swift`.
+  public let sourceFilePath: String?
+
   public var signatureString: String {
     self.swiftDecl.signatureString
   }
@@ -386,12 +390,14 @@ public final class ExtractedFunc: ExtractedSwiftDecl, CustomStringConvertible {
     name: String,
     apiKind: SwiftAPIKind,
     functionSignature: SwiftFunctionSignature,
+    sourceFilePath: String? = nil,
   ) {
     self.module = module
     self.name = name
     self.swiftDecl = swiftDecl
     self.apiKind = apiKind
     self.functionSignature = functionSignature
+    self.sourceFilePath = sourceFilePath
   }
 
   public var description: String {
@@ -414,7 +420,8 @@ public final class ExtractedFunc: ExtractedSwiftDecl, CustomStringConvertible {
       swiftDecl: swiftDecl,
       name: name,
       apiKind: apiKind,
-      functionSignature: functionSignature
+      functionSignature: functionSignature,
+      sourceFilePath: sourceFilePath
     )
   }
 
@@ -465,7 +472,8 @@ public final class ExtractedFunc: ExtractedSwiftDecl, CustomStringConvertible {
           swiftDecl: swiftDecl,
           name: name,
           apiKind: apiKind,
-          functionSignature: newSignature
+          functionSignature: newSignature,
+          sourceFilePath: sourceFilePath
         )
       )
     }

Sources/SwiftExtract/SwiftAnalysisVisitor.swift

@@ -227,6 +227,7 @@ final class SwiftAnalysisVisitor {
       name: node.name.text.unescapedSwiftName,
       apiKind: apiKind,
       functionSignature: signature,
+      sourceFilePath: sourceFilePath,
     )
 
     log.debug("Record extracted method \(node.qualifiedNameForDebug)")
@@ -267,6 +268,7 @@ final class SwiftAnalysisVisitor {
           name: caseName,
           apiKind: .enumCase,
           functionSignature: signature,
+          sourceFilePath: sourceFilePath,
         )
 
         let extractedCase = ExtractedEnumCase(
@@ -316,6 +318,7 @@ final class SwiftAnalysisVisitor {
           in: typeContext,
           kind: .getter,
           name: varName,
+          sourceFilePath: sourceFilePath,
         )
       }
       if supportedAccessors.contains(.set) {
@@ -324,6 +327,7 @@ final class SwiftAnalysisVisitor {
           in: typeContext,
           kind: .setter,
           name: varName,
+          sourceFilePath: sourceFilePath,
         )
       }
     } catch {
@@ -370,6 +374,7 @@ final class SwiftAnalysisVisitor {
       name: "init",
       apiKind: .initializer,
       functionSignature: signature,
+      sourceFilePath: sourceFilePath,
     )
 
     typeContext.initializers.append(extracted)
@@ -397,6 +402,7 @@ final class SwiftAnalysisVisitor {
           in: typeContext,
           kind: .subscriptGetter,
           name: name,
+          sourceFilePath: sourceFilePath,
         )
       }
       if accessors.contains(.set) {
@@ -405,6 +411,7 @@ final class SwiftAnalysisVisitor {
           in: typeContext,
           kind: .subscriptSetter,
           name: name,
+          sourceFilePath: sourceFilePath,
         )
       }
     } catch {
@@ -445,6 +452,7 @@ final class SwiftAnalysisVisitor {
     in typeContext: ExtractedNominalType?,
     kind: SwiftAPIKind,
     name: String,
+    sourceFilePath: String,
   ) throws {
     let signature: SwiftFunctionSignature
 
@@ -474,6 +482,7 @@ final class SwiftAnalysisVisitor {
       name: name,
       apiKind: kind,
       functionSignature: signature,
+      sourceFilePath: sourceFilePath,
     )
 
     log.debug(