Translate all code to English (#1836)

* Review the EN heading format.

* Fix pythontutor headings.

* Fix pythontutor headings.

* bug fixes

* Fix headings in **/summary.md

* Revisit the CN-to-EN translation for Python code using Claude-4.5

* Revisit the CN-to-EN translation for Java code using Claude-4.5

* Revisit the CN-to-EN translation for Cpp code using Claude-4.5.

* Fix the dictionary.

* Fix cpp code translation for the multipart strings.

* Translate Go code to English.

* Update workflows to test EN code.

* Add EN translation for C.

* Add EN translation for CSharp.

* Add EN translation for Swift.

* Trigger the CI check.

* Revert.

* Update en/hash_map.md

* Add the EN version of Dart code.

* Add the EN version of Kotlin code.

* Add missing code files.

* Add the EN version of JavaScript code.

* Add the EN version of TypeScript code.

* Fix the workflows.

* Add the EN version of Ruby code.

* Add the EN version of Rust code.

* Update the CI check for the English version  code.

* Update Python CI check.

* Fix cmakelists for en/C code.

* Fix Ruby comments

en/codes/go/chapter_graph/graph_dfs.go

@@ -0,0 +1,36 @@
+// File: graph_dfs.go
+// Created Time: 2023-02-18
+// Author: Reanon (793584285@qq.com)
+
+package chapter_graph
+
+import (
+	. "github.com/krahets/hello-algo/pkg"
+)
+
+/* Depth-first traversal helper function */
+func dfs(g *graphAdjList, visited map[Vertex]struct{}, res *[]Vertex, vet Vertex) {
+	// append operation returns a new reference, must reassign original reference to new slice's reference
+	*res = append(*res, vet)
+	visited[vet] = struct{}{}
+	// Traverse all adjacent vertices of this vertex
+	for _, adjVet := range g.adjList[vet] {
+		_, isExist := visited[adjVet]
+		// Recursively visit adjacent vertices
+		if !isExist {
+			dfs(g, visited, res, adjVet)
+		}
+	}
+}
+
+/* Depth-first traversal */
+// Use adjacency list to represent the graph, in order to obtain all adjacent vertices of a specified vertex
+func graphDFS(g *graphAdjList, startVet Vertex) []Vertex {
+	// Vertex traversal sequence
+	res := make([]Vertex, 0)
+	// Hash set for recording vertices that have been visited
+	visited := make(map[Vertex]struct{})
+	dfs(g, visited, &res, startVet)
+	// Return vertex traversal sequence
+	return res
+}