EventIndexPanel: Reword the enable/disable setting.

src/components/views/settings/EventIndexPanel.js

@@ -114,7 +114,7 @@ export default class EventIndexPanel extends React.Component {
                     <LabelledToggleSwitch
                         value={this.state.eventIndexingEnabled}
                         onChange={this._onEventIndexingEnabledChange}
-                        label={_t('Enable message downloading')} />
+                        label={_t('Download and index encrypted messages')} />
 
                     <Field
                         id={"crawlerSleepTimeMs"}

src/i18n/strings/en_EN.json

@@ -738,7 +738,7 @@
     "Encrypted search": "Encrypted search",
     "To enable search in encrypted rooms, Riot needs to run a background process to download historical messages from those rooms to your computer.": "To enable search in encrypted rooms, Riot needs to run a background process to download historical messages from those rooms to your computer.",
     "Message disk usage:": "Message disk usage:",
-    "Enable message downloading": "Enable message downloading",
+    "Download and index encrypted messages": "Download and index encrypted messages",
     "Message downloading sleep time(ms)": "Message downloading sleep time(ms)",
     "Preferences": "Preferences",
     "Composer": "Composer",