clang-tidy: apply readability-redundant-control-flow fixes

Source/cmCPluginAPI.cxx

@@ -733,7 +733,6 @@ void CCONV cmSourceFileSetName(void* arg, const char* name, const char* dir,
     e << " ." << *ext;
   }
   cmSystemTools::Error(e.str().c_str());
-  return;
 }
 
 void CCONV cmSourceFileSetName2(void* arg, const char* name, const char* dir,

Source/cmCoreTryCompile.cxx

@@ -901,5 +901,4 @@ void cmCoreTryCompile::FindOutputFile(const std::string& targetName,
   emsg << cmWrap("  " + this->BinaryDirectory, searchDirs, tmpOutputFile, "\n")
        << "\n";
   this->FindErrorMessage = emsg.str();
-  return;
 }

Source/cmExportLibraryDependenciesCommand.cxx

@@ -180,5 +180,4 @@ void cmExportLibraryDependenciesCommand::ConstFinalPass() const
     }
   }
   fout << "endif()\n";
-  return;
 }

Source/cmExtraCodeBlocksGenerator.cxx

@@ -137,7 +137,6 @@ void Tree::InsertPath(const std::vector<std::string>& splitted,
   // last part of splitted
   newFolder.files.push_back(fileName);
   folders.push_back(newFolder);
-  return;
 }
 
 void Tree::BuildVirtualFolder(cmXMLWriter& xml) const