Be more specific about which alternative space characters should work…

… as group symbols

The `\s` character class (or the `string.isspace()` method) could match
characters like new lines that we probably don’t want to consider as potential
group symbols in numbers.

babel/numbers.py

@@ -862,6 +862,15 @@ def __init__(self, message: str, suggestions: list[str] | None = None) -> None:
         self.suggestions = suggestions
 
 
+SPACE_CHARS = {
+    ' ',  # regular space
+    '\xa0',  # non-breakable space
+    '\u202f',  # narrow non-breakable space
+}
+
+SPACE_CHARS_RE = re.compile('|'.join(SPACE_CHARS))
+
+
 def parse_number(string: str, locale: Locale | str | None = LC_NUMERIC) -> int:
     """Parse localized number string into an integer.
 
@@ -885,12 +894,12 @@ def parse_number(string: str, locale: Locale | str | None = LC_NUMERIC) -> int:
     group_symbol = get_group_symbol(locale)
 
     if (
-        re.match(r'\s', group_symbol) and  # if the grouping symbol is a kind of space,
+        group_symbol in SPACE_CHARS and  # if the grouping symbol is a kind of space,
         group_symbol not in string and  # and the string to be parsed does not contain it,
-        re.search(r'\s', string)  # but it does contain any other kind of space instead,
+        SPACE_CHARS_RE.search(string)  # but it does contain any other kind of space instead,
     ):
         # ... it's reasonable to assume it is taking the place of the grouping symbol.
-        string = re.sub(r'\s', group_symbol, string)
+        string = SPACE_CHARS_RE.sub(group_symbol, string)
 
     try:
         return int(string.replace(group_symbol, ''))
@@ -940,12 +949,12 @@ def parse_decimal(string: str, locale: Locale | str | None = LC_NUMERIC, strict:
     decimal_symbol = get_decimal_symbol(locale)
 
     if not strict and (
-        re.match(r'\s', group_symbol) and  # if the grouping symbol is a kind of space,
+        group_symbol in SPACE_CHARS and  # if the grouping symbol is a kind of space,
         group_symbol not in string and  # and the string to be parsed does not contain it,
-        re.search(r'\s', string)  # but it does contain any other kind of space instead,
+        SPACE_CHARS_RE.search(string)  # but it does contain any other kind of space instead,
     ):
         # ... it's reasonable to assume it is taking the place of the grouping symbol.
-        string = re.sub(r'\s', group_symbol, string)
+        string = SPACE_CHARS_RE.sub(group_symbol, string)
 
     try:
         parsed = decimal.Decimal(string.replace(group_symbol, '')