Use C locale instead of en_US.UTF-8 to force English language

Some users reported that en_US.UTF-8 is not available on their systems, leading
to warnings in the command log. "C" also forces the language to English, and is
guaranteed to be available everywhere.

Author: stefanhaller

pkg/commands/git_commands/rebase.go

@@ -244,8 +244,8 @@ func (self *RebaseCommands) PrepareInteractiveRebaseCommand(opts PrepareInteract
 
 	cmdObj.AddEnvVars(
 		"DEBUG="+debug,
-		"LANG=en_US.UTF-8",   // Force using EN as language
-		"LC_ALL=en_US.UTF-8", // Force using EN as language
+		"LANG=C",   // Force using English language
+		"LC_ALL=C", // Force using English language
 		"GIT_SEQUENCE_EDITOR="+gitSequenceEditor,
 	)
 
@@ -277,8 +277,8 @@ func (self *RebaseCommands) GitRebaseEditTodo(todosFileContent []byte) error {
 
 	cmdObj.AddEnvVars(
 		"DEBUG="+debug,
-		"LANG=en_US.UTF-8",   // Force using EN as language
-		"LC_ALL=en_US.UTF-8", // Force using EN as language
+		"LANG=C",   // Force using English language
+		"LC_ALL=C", // Force using English language
 		"GIT_EDITOR="+ex,
 		"GIT_SEQUENCE_EDITOR="+ex,
 	)

pkg/commands/oscommands/cmd_obj_runner.go

@@ -330,7 +330,7 @@ func (self *cmdObjRunner) runAndDetectCredentialRequest(
 	promptUserForCredential func(CredentialType) <-chan string,
 ) error {
 	// setting the output to english so we can parse it for a username/password request
-	cmdObj.AddEnvVars("LANG=en_US.UTF-8", "LC_ALL=en_US.UTF-8")
+	cmdObj.AddEnvVars("LANG=C", "LC_ALL=C")
 
 	return self.runAndStreamAux(cmdObj, func(handler *cmdHandler, cmdWriter io.Writer) {
 		tr := io.TeeReader(handler.stdoutPipe, cmdWriter)