Enable the RUF001 lint in Ruff

.ruff.toml

@@ -70,7 +70,6 @@ ignore = [
     "UP031",   # Use format specifiers instead of percent format
     "UP032",   # Use f-string instead of `format` call
     # Ruff-specific rules ('RUF')
-    "RUF001",  # String contains ambiguous {}. Did you mean {}?
     "RUF012",  # Mutable class attributes should be annotated with `typing.ClassVar`
     "RUF021",  # Parenthesize `a and b` expressions when chaining `and` and `or` together, to make the precedence clear
     "RUF022",  # `__all__` is not sorted
@@ -321,7 +320,7 @@ logger-objects = [
 "sphinx/ext/autodoc/importer.py" = ["D402"]
 "sphinx/util/requests.py" = ["D402"]
 
-"sphinx/search/*" = ["E501"]
+"sphinx/search/*" = ["E501", "RUF001"]
 
 # whitelist ``token`` in date format parsing
 "sphinx/util/i18n.py" = ["S105"]
@@ -334,6 +333,7 @@ logger-objects = [
     "ANN",  # tests don't need annotations
     "D402",
     "PLC1901",  # whitelist comparisons to the empty string ('')
+    "RUF001",  # ambiguous unicode character
     "S301",  # allow use of ``pickle``
     "S403",  # allow use of ``pickle``
     "T201",  # whitelist ``print`` for tests

sphinx/util/texescape.py

@@ -29,8 +29,8 @@ tex_replacements = [
     # map some special Unicode characters to similar ASCII ones
     # (even for Unicode LaTeX as may not be supported by OpenType font)
     ('⎽', r'\_'),
-    ('ℯ', r'e'),
-    ('ⅈ', r'i'),
+    ('ℯ', r'e'),  # U+212F # NoQA: RUF001
+    ('ⅈ', r'i'),  # U+2148 # NoQA: RUF001
     # Greek alphabet not escaped: pdflatex handles it via textalpha and inputenc
     # OHM SIGN U+2126 is handled by LaTeX textcomp package
 ]
@@ -63,7 +63,7 @@ unicode_tex_replacements = [
     ('±', r'\(\pm\)'),
     ('→', r'\(\rightarrow\)'),
     ('‣', r'\(\rightarrow\)'),
-    ('–', r'\textendash{}'),
+    ('\N{EN DASH}', r'\textendash{}'),
     # superscript
     ('⁰', r'\(\sp{\text{0}}\)'),
     ('¹', r'\(\sp{\text{1}}\)'),

sphinx/writers/texinfo.py

@@ -1503,7 +1503,7 @@ class TexinfoTranslator(SphinxTranslator):
             self.first_param = 0
         text = self.escape(node.astext())
         # replace no-break spaces with normal ones
-        text = text.replace(' ', '@w{ }')
+        text = text.replace('\N{NO-BREAK SPACE}', '@w{ }')
         self.body.append(text)
         raise nodes.SkipNode