add global keyboard shortcut for toggling docs

This handles the cases when the editor is not active and the docs pane
is not active and the terminal is not active.

src/components/SettingsDrawer.tsx

@@ -8,6 +8,9 @@ import {
     Classes,
     Drawer,
     FormGroup,
+    Hotkey,
+    Hotkeys,
+    HotkeysTarget,
     Position,
     Switch,
     Tooltip,
@@ -17,7 +20,7 @@ import React from 'react';
 import { connect } from 'react-redux';
 import { Action, Dispatch } from '../actions';
 import { closeSettings, openAboutDialog } from '../actions/app';
-import { setBoolean } from '../actions/settings';
+import { setBoolean, toggleBoolean } from '../actions/settings';
 import { RootState } from '../reducers';
 import { pseudolocalize } from '../settings/i18n';
 import {
@@ -47,10 +50,12 @@ type DispatchProps = {
     onDarkModeChanged: (checked: boolean) => void;
     onFlashCurrentProgramChanged: (checked: boolean) => void;
     onAbout: () => void;
+    onToggleDocs: () => void;
 };
 
 type SettingsProps = StateProps & DispatchProps & WithI18nProps;
 
+@HotkeysTarget
 class SettingsDrawer extends React.PureComponent<SettingsProps> {
     render(): JSX.Element {
         const {
@@ -223,6 +228,22 @@ class SettingsDrawer extends React.PureComponent<SettingsProps> {
             </Drawer>
         );
     }
+
+    renderHotkeys(): JSX.Element {
+        return (
+            <Hotkeys>
+                <Hotkey
+                    combo="mod+d"
+                    label={this.props.i18n.translate(
+                        SettingsStringId.AppearanceDocumentationTooltip,
+                    )}
+                    global={true}
+                    preventDefault={true}
+                    onKeyDown={() => this.props.onToggleDocs()}
+                />
+            </Hotkeys>
+        );
+    }
 }
 
 const mapStateToProps = (state: RootState): StateProps => ({
@@ -241,6 +262,7 @@ const mapDispatchToProps = (dispatch: Dispatch): DispatchProps => ({
     onFlashCurrentProgramChanged: (checked): Action =>
         dispatch(setBoolean(SettingId.FlashCurrentProgram, checked)),
     onAbout: (): Action => dispatch(openAboutDialog()),
+    onToggleDocs: (): Action => dispatch(toggleBoolean(SettingId.ShowDocs)),
 });
 
 export default connect(