Remove the view command and the editor setting with it

`view` was the last user of `editor`, so leaving the setting behind would
have made it exactly what `gitkey` was until recently: documented,
parsed, and doing nothing. It is gone from the struct, the template, the
environment, `config -k` and the settings table.

Both names are free for aliases now, as `open` already was.

The tests that used `editor` as their example of a project-overridable
setting use `gitkey` instead, which is the same kind of thing and still
exists.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

config.go

@@ -33,7 +33,6 @@ type Config struct {
 	GitName     string // git user.name to set globally ("" = leave alone)
 	GitEmail    string // git user.email to set globally ("" = leave alone)
 	PushDefault string // git push.default to set globally ("" = leave alone)
-	Editor      string // editor/opener used as fallback by `view` ("" = coda)
 	Mirror      string // truthy -> `push` also mirrors via `pushremote`
 	SecretScan  string // falsy -> `push` skips the credential scan
 	Remotes     []RemoteTarget
@@ -320,7 +319,7 @@ func writeConfigTemplate(path string) {
 	b.WriteString("# gitname     = Your Name\n")
 	b.WriteString("# gitemail    = you@example.com\n")
 	b.WriteString("# pushdefault = matching\n")
-	b.WriteString("# editor      = code\n\n")
+	b.WriteString("\n")
 	b.WriteString("# --- public mirrors for `pushremote` ---\n")
 	b.WriteString("# One 'remote.<name>.*' block per server. `pushremote` pushes to all\n")
 	b.WriteString("# of them, `pushremote @gitlab` to a single one. <name> is also the\n")
@@ -409,7 +408,6 @@ func applyConfig(c *Config, m map[string]string) {
 	set("gitname", &c.GitName)
 	set("gitemail", &c.GitEmail)
 	set("pushdefault", &c.PushDefault)
-	set("editor", &c.Editor)
 	set("remotes", &c.RemoteNames)
 	set("mirror", &c.Mirror)
 	set("secretscan", &c.SecretScan)
@@ -505,7 +503,6 @@ func applyEnv(c *Config) {
 	env("MGSH_GITNAME", &c.GitName)
 	env("MGSH_GITEMAIL", &c.GitEmail)
 	env("MGSH_PUSHDEFAULT", &c.PushDefault)
-	env("MGSH_EDITOR", &c.Editor)
 	env("MGSH_REMOTES", &c.RemoteNames)
 	env("MGSH_MIRROR", &c.Mirror)
 	env("MGSH_SECRETSCAN", &c.SecretScan)