Add key binding for switching from the commit message panel to an editor

This is useful for when you begin to type the message in lazygit's commit panel,
and then realize that you'd rather use your editor's more powerful editing
capabilities. Pressing <c-o> will take you right there.

pkg/config/user_config.go

@@ -132,16 +132,17 @@ type UpdateConfig struct {
 }
 
 type KeybindingConfig struct {
-	Universal   KeybindingUniversalConfig   `yaml:"universal"`
-	Status      KeybindingStatusConfig      `yaml:"status"`
-	Files       KeybindingFilesConfig       `yaml:"files"`
-	Branches    KeybindingBranchesConfig    `yaml:"branches"`
-	Worktrees   KeybindingWorktreesConfig   `yaml:"worktrees"`
-	Commits     KeybindingCommitsConfig     `yaml:"commits"`
-	Stash       KeybindingStashConfig       `yaml:"stash"`
-	CommitFiles KeybindingCommitFilesConfig `yaml:"commitFiles"`
-	Main        KeybindingMainConfig        `yaml:"main"`
-	Submodules  KeybindingSubmodulesConfig  `yaml:"submodules"`
+	Universal     KeybindingUniversalConfig     `yaml:"universal"`
+	Status        KeybindingStatusConfig        `yaml:"status"`
+	Files         KeybindingFilesConfig         `yaml:"files"`
+	Branches      KeybindingBranchesConfig      `yaml:"branches"`
+	Worktrees     KeybindingWorktreesConfig     `yaml:"worktrees"`
+	Commits       KeybindingCommitsConfig       `yaml:"commits"`
+	Stash         KeybindingStashConfig         `yaml:"stash"`
+	CommitFiles   KeybindingCommitFilesConfig   `yaml:"commitFiles"`
+	Main          KeybindingMainConfig          `yaml:"main"`
+	Submodules    KeybindingSubmodulesConfig    `yaml:"submodules"`
+	CommitMessage KeybindingCommitMessageConfig `yaml:"commitMessage"`
 }
 
 // damn looks like we have some inconsistencies here with -alt and -alt1
@@ -305,6 +306,10 @@ type KeybindingSubmodulesConfig struct {
 	BulkMenu string `yaml:"bulkMenu"`
 }
 
+type KeybindingCommitMessageConfig struct {
+	SwitchToEditor string `yaml:"switchToEditor"`
+}
+
 // OSConfig contains config on the level of the os
 type OSConfig struct {
 	// Command for editing a file. Should contain "{{filename}}".
@@ -652,6 +657,9 @@ func GetDefaultConfig() *UserConfig {
 				Update:   "u",
 				BulkMenu: "b",
 			},
+			CommitMessage: KeybindingCommitMessageConfig{
+				SwitchToEditor: "<c-o>",
+			},
 		},
 		OS:                           OSConfig{},
 		DisableStartupPopups:         false,