Allow to use arobase in variables

fix #1028

umap/static/umap/js/umap.core.js

@@ -174,7 +174,7 @@ L.Util.greedyTemplate = (str, data, ignore) => {
   }
 
   return str.replace(
-    /\{ *([\w_\:\.\|]+)(?:\|("[^"]*"))? *\}/g,
+    /\{ *([\w_\:\.\|@]+)(?:\|("[^"]*"))? *\}/g,
     (str, key, staticFallback) => {
       const vars = key.split('|')
       let value

umap/static/umap/test/Util.js

@@ -236,6 +236,15 @@ describe('L.Util', function () {
       )
     })
 
+    it('should accept arobase', function () {
+      assert.equal(
+        L.Util.greedyTemplate('A phrase with a {@variable}.', {
+          '@variable': 'value',
+        }),
+        'A phrase with a value.'
+      )
+    })
+
     it('should replace even with ignore if key is found', function () {
       assert.equal(
         L.Util.greedyTemplate(