gh-37246: minor details in modular
    
namely

- use ruff to fix some containement tests

- add links to some error codes in the doc

- plus some http to https

### 📝 Checklist

- [x] The title is concise, informative, and self-explanatory.
- [x] The description explains in detail what this PR is about.
    
URL: #37246
Reported by: Frédéric Chapoton
Reviewer(s): Matthias Köppe

Author: Release Manager

src/sage/modular/arithgroup/arithgroup_generic.py

@@ -571,7 +571,7 @@ def is_subgroup(self, right):
 
         w = self.gens()
         for g in w:
-            if not (g in right):
+            if g not in right:
                 return False
         return True
 

src/sage/modular/arithgroup/arithgroup_perm.py

@@ -816,7 +816,7 @@ def relabel(self, inplace=True):
         """
         if hasattr(self,'_canonical_label_group'):
             if inplace:
-                if not (self is self._canonical_label_group):
+                if self is not self._canonical_label_group:
                     self.__dict__ = self._canonical_label_group.__dict__
                     self._canonical_label_group = self
             else:
@@ -1811,7 +1811,7 @@ def cusp_widths(self,exp=False):
                 c1 = min(L.orbit(inv(c0)))
                 cusps.remove(c1)
                 if exp:
-                    if not len(c) in widths:
+                    if len(c) not in widths:
                         widths[len(c)] = 0
                     widths[len(c)] += 1
                 else:

src/sage/modular/arithgroup/congroup_gammaH.py

@@ -1045,7 +1045,7 @@ def is_subgroup(self, other):
             # difficult case
             t = other._list_of_elements_in_H()
             for x in self._generators_for_H():
-                if not (x in t):
+                if x not in t:
                     return False
             return True
 
@@ -1402,7 +1402,7 @@ def _list_subgroup(N, gens):
             raise ValueError("gen (=%s) is not in (Z/%sZ)^*" % (g, N))
         gk = int(g) % N
         sbgrp = [gk]
-        while not (gk in H):
+        while gk not in H:
             gk = (gk * g) % N
             sbgrp.append(gk)
         H = {(x * h) % N for x in sbgrp for h in H}

src/sage/modular/btquotients/btquotient.py

@@ -695,7 +695,7 @@ def edge_between_vertices(self, v1, v2, normalized=False):
 
         - 2x2 integer matrix, representing the edge from ``v1`` to
           ``v2``.  If ``v1`` and ``v2`` are not at distance `1`, raise
-          a ``ValueError``.
+          a :class:`ValueError`.
 
         EXAMPLES::
 

src/sage/modular/hecke/ambient_module.py

@@ -392,7 +392,7 @@ def degeneracy_map(self, codomain, t=1):
                               "level (=%s) and t (=%s) must be a divisor of the quotient") % (self.level(), level, t))
 
         eps = self.character()
-        if not (eps is None) and level % eps.conductor() != 0:
+        if eps is not None and level % eps.conductor() != 0:
             raise ArithmeticError("the conductor of the character of this space "
                                   "(=%s) must be divisible by the level (=%s)" % (eps.conductor(), level))
 

src/sage/modular/hecke/module.py

@@ -456,7 +456,7 @@ def rank(self):
         r"""
         Return the rank of this module over its base ring.
 
-        This raises a ``NotImplementedError``, since this is an
+        This raises a :class:`NotImplementedError`, since this is an
         abstract base class.
 
         EXAMPLES::
@@ -473,7 +473,7 @@ def submodule(self, X):
         Return the submodule of ``self`` corresponding to ``X``.
 
         As this is an abstract base class, this raises a
-        ``NotImplementedError``.
+        :class:`NotImplementedError`.
 
         EXAMPLES::
 
@@ -739,7 +739,7 @@ def ambient_hecke_module(self):
         r"""
         Return the ambient module associated to this module.
 
-        As this is an abstract base class, raise ``NotImplementedError``.
+        As this is an abstract base class, raise :class:`NotImplementedError`.
 
         EXAMPLES::
 
@@ -1501,7 +1501,7 @@ def is_simple(self):
         Return ``True`` if this space is simple as a module for the
         corresponding Hecke algebra.
 
-        Raises ``NotImplementedError``, as this is an abstract base
+        This raises :class:`NotImplementedError`, as this is an abstract base
         class.
 
         EXAMPLES::

src/sage/modular/hecke/submodule.py

@@ -95,7 +95,7 @@ def __init__(self, ambient, submodule, dual_free_module=None, check=True):
         module.HeckeModule_free_module.__init__(self, ambient.base_ring(),
                                                 ambient.level(),
                                                 ambient.weight())
-        if not (dual_free_module is None):
+        if dual_free_module is not None:
             if not is_FreeModule(dual_free_module):
                 raise TypeError("dual_free_module must be a free module")
             if dual_free_module.rank() != submodule.rank():
@@ -960,7 +960,7 @@ def submodule_from_nonembedded_module(self, V, Vdual=None, check=True):
         # so fast, and their are asymptotically fast algorithms.
         A = M_V * M_E
         V = A.row_space()
-        if not (Vdual is None):
+        if Vdual is not None:
             E = self.dual_free_module()
             M_Vdual = Vdual.matrix()
             M_E = E.matrix()

src/sage/modular/local_comp/smoothchar.py

@@ -802,7 +802,7 @@ def _test_unitgens(self, **options):
                         g = I.small_residue(g)
                     else:  # I is an ideal of ZZ
                         g = g % (I.gen())
-                if not (g - 1 in I):
+                if g - 1 not in I:
                     T.fail("For generator g=%s, g^%s = %s, which is not 1 mod I" % (gens[i], exps[i], g))
             I = self.prime() if self.number_field() == QQ else self.ideal(1)
             T.assertEqual(gens[-1].valuation(I), 1)

src/sage/modular/modform/constructor.py

@@ -330,7 +330,7 @@ def ModularForms(group=1,
 
     if use_cache and key in _cache:
         M = _cache[key]()
-        if not (M is None):
+        if M is not None:
             M.set_precision(prec)
             return M
 

src/sage/modular/modform/space.py

@@ -365,7 +365,7 @@ def has_character(self):
             sage: CuspForms(DirichletGroup(11).0,3).has_character()
             True
         """
-        return not self.character() is None
+        return self.character() is not None
 
     def is_ambient(self):
         """
@@ -1929,6 +1929,6 @@ def contains_each(V, B):
         False
     """
     for b in B:
-        if not (b in V):
+        if b not in V:
             return False
     return True