Trac #34466: fix various linter errors

This should make the linters on GitHub happy.

URL: https://trac.sagemath.org/34466
Reported by: lorenz
Ticket author(s): Lorenz Panny
Reviewer(s): Frédéric Chapoton

src/sage/algebras/clifford_algebra.py

@@ -2984,7 +2984,7 @@ def groebner_basis(self, term_order=None, reduced=True):
                 from sage.algebras.exterior_algebra_groebner import GroebnerStrategyDegLex as strategy
             else:
                 raise ValueError("invalid term order")
-        if strategy == type(self._groebner_strategy):
+        if isinstance(self._groebner_strategy, strategy):
             if self._reduced or not reduced:
                 return self._groebner_strategy.groebner_basis
             self._reduced = reduced

src/sage/algebras/hecke_algebras/cubic_hecke_algebra.py

@@ -1628,7 +1628,7 @@ def _tietze_to_finite_sub_basis_monomial(self, tietze_tup):
     def _create_matrix_list_for_one(self, representation_type):
         r"""
         Return the matrix list for the given representation type
-        for ``self.one()`.
+        for ``self.one()``.
 
         EXAMPLES::
 
@@ -2366,8 +2366,8 @@ def _reduce_all_gen_powers(self, braid_tietze):
     @cached_method
     def _reduce_gen_power(self, k):
         r"""
-        Return the ``k``-th power on an arbitrary generator,
-        for example ``c0^k` .
+        Return the `k`-th power on an arbitrary generator,
+        for example `c_0^k`.
 
         INPUT:
 

src/sage/groups/cubic_braid.py

@@ -963,6 +963,7 @@ def _test_matrix_group(self, **options):
         - Construction of matrix group was faithful.
         - Coercion maps to and from matrix group exist and are
           inverse to each other.
+
         EXAMPLES::
 
             sage: CBG2 = CubicBraidGroup(2)

src/sage/schemes/elliptic_curves/hom_velusqrt.py

@@ -322,11 +322,14 @@ def prod_with_derivative(pairs):
     class _aux:
         def __init__(self, f, df):
             self.f, self.df = f, df
+
         def __mul__(self, other):
             return _aux(self.f * other.f, self.df * other.f + self.f * other.df)
+
         def __iter__(self):
             yield self.f
             yield self.df
+
     return tuple(prod(_aux(*tup) for tup in pairs))