vega: Only escape field.

Unnecesary escaping for `title` and labels was added in #81.

Author: daavoo

src/dvc_render/vega.py

@@ -81,7 +81,7 @@ def get_filled_template(
                         f"Template '{self.template.name}' "
                         f"is not using '{anchor}' anchor"
                     )
-            else:
+            elif name in {"x", "y"}:
                 value = self.template.escape_special_characters(value)
             content = self.template.fill_anchor(content, name, value)
 

tests/test_vega.py

@@ -173,6 +173,6 @@ def test_escape_special_characters():
     assert filled["data"]["values"][0] == datapoints[0]
     # field and title yes
     assert filled["encoding"]["x"]["field"] == "foo\\.bar\\[0\\]"
-    assert filled["encoding"]["x"]["title"] == "foo\\.bar\\[0\\]"
+    assert filled["encoding"]["x"]["title"] == "foo.bar[0]"
     assert filled["encoding"]["y"]["field"] == "foo\\.bar\\[1\\]"
-    assert filled["encoding"]["y"]["title"] == "foo\\.bar\\[1\\]"
+    assert filled["encoding"]["y"]["title"] == "foo.bar[1]"