Upgrade eslint (#1014)

It's apparently forced now to use the eslint.config.js instead of
.eslintrc

It got more strict with requiring the underscore on unused vars like
`catch(_err)` , but that was all

Closes #1012
Closes #995
Closes #992

## Launch Checklist

<!-- Thanks for the PR! Feel free to add or remove items from the
checklist. -->


 - [ ] Briefly describe the changes in this PR.
 - [ ] Link to related issues.
- [ ] Include before/after visuals or gifs if this PR includes visual
changes.
 - [ ] Write tests for all new functionality.
 - [ ] Add an entry to `CHANGELOG.md` under the `## main` section.

src/components/InputUrl.tsx

@@ -15,7 +15,7 @@ function validate(url: string, t: TFunction): JSX.Element | undefined {
       const urlObj = new URL(url);
       return urlObj.protocol;
     }
-    catch (err) {
+    catch (_err) {
       return undefined;
     }
   };

src/components/MapMaplibreGl.tsx

@@ -103,7 +103,7 @@ class MapMaplibreGlInternal extends React.Component<MapMaplibreGlInternalProps,
     let should = false;
     try {
       should = JSON.stringify(this.props) !== JSON.stringify(nextProps) || JSON.stringify(this.state) !== JSON.stringify(nextState);
-    } catch(e) {
+    } catch(_e) {
       // no biggie, carry on
     }
     return should;
@@ -161,7 +161,7 @@ class MapMaplibreGlInternal extends React.Component<MapMaplibreGlInternalProps,
     map.showCollisionBoxes = mapOpts.showCollisionBoxes!;
     map.showOverdrawInspector = mapOpts.showOverdrawInspector!;
 
-    let geocoder = this.initGeocoder(map);
+    const geocoder = this.initGeocoder(map);
 
     const zoomControl = new ZoomControl();
     map.addControl(zoomControl, 'top-right');