[FIX] account_financial_report: fix the order of vat tag report lines

- Currently the lines of the vat tax tag report are not properly sorted
  leading to similar tags (only differing by their sign) ending up far
  apart making it difficult to see when values have to be subtracted
  from another to get the final result.
- This patch sorts the lines first by the code (currently always empty)
  second by the name of the tag (without the sign) and only third by
  the sign (to always have the '+' in front of the '-' tag)

account_financial_report/report/vat_report.py

@@ -154,7 +154,12 @@ def _get_tags_data(self, tags_ids):
         tags = self.env["account.account.tag"].browse(tags_ids)
         tags_data = {}
         for tag in tags:
-            tags_data.update({tag.id: {"code": "", "name": tag.name}})
+            sign = ""
+            name = tag.name
+            if tag.name[0] in ("+", "-"):
+                name = tag.name[1:]
+                sign = tag.name[0]
+            tags_data.update({tag.id: {"code": "", "name": name, "sign": sign}})
         return tags_data
 
     def _get_vat_report_tag_data(self, vat_report_data, tax_data, tax_detail):
@@ -185,8 +190,10 @@ def _get_vat_report_tag_data(self, vat_report_data, tax_data, tax_detail):
                         vat_report[tag_id]["tax"] += tax_move_line["tax"]
         tags_data = self._get_tags_data(vat_report.keys())
         vat_report_list = []
-        for tag_id in vat_report.keys():
-            vat_report[tag_id]["name"] = tags_data[tag_id]["name"]
+        for tag_id in sorted(
+            vat_report.keys(), key=lambda t: "{code}{name}{sign}".format(**tags_data[t])
+        ):
+            vat_report[tag_id]["name"] = "{sign}{name}".format(**tags_data[tag_id])
             vat_report[tag_id]["code"] = tags_data[tag_id]["code"]
             if tax_detail:
                 vat_report[tag_id]["taxes"] = []