fix compiler error, and add /hist to robots.txt disallow

Author: tayloraswift

Sources/SwiftinitServer/Endpoints/Interactive/Swiftinit.RobotsEndpoint.swift

@@ -47,6 +47,7 @@ extension Swiftinit.RobotsEndpoint:PublicEndpoint
             User-agent: *
             Disallow: /admin/
             Disallow: /auth/
+            Disallow: /hist/
             Disallow: /reference/
             Disallow: /telescope/
 

Sources/SymbolGraphCompiler/Declarations/Compiler.Decl.swift

@@ -101,7 +101,7 @@ extension Compiler.Decl
 
         let language:Phylum.Language
         if  case .swift = culture.language,
-            case .c = symbol.language
+            case .c = (copy symbol).language
         {
             language = .c
         }