fix failing doctests

Author: fchapoton

src/sage/combinat/permutation.py

@@ -7268,7 +7268,7 @@ def algebra(self, base_ring, category=None):
             Symmetric group algebra of order 4 over Rational Field
 
             sage: A.category()                                                          # optional - sage.combinat sage.modules
-            Join of Category of coxeter group algebras over Rational Field
+            Join of Category of Coxeter group algebras over Rational Field
                 and Category of finite group algebras over Rational Field
                 and Category of finite dimensional cellular algebras
                     with basis over Rational Field

src/sage/groups/matrix_gps/coxeter_group.py

@@ -253,21 +253,21 @@ def __init__(self, coxeter_matrix, base_ring, index_set):
         We check that :trac:`16630` is fixed::
 
             sage: CoxeterGroup(['D',4], base_ring=QQ).category()
-            Category of finite irreducible coxeter groups
+            Category of finite irreducible Coxeter groups
 
             sage: # needs sage.rings.number_field
             sage: CoxeterGroup(['H',4], base_ring=QQbar).category()
-            Category of finite irreducible coxeter groups
+            Category of finite irreducible Coxeter groups
             sage: F = CoxeterGroups().Finite()
             sage: all(CoxeterGroup([letter,i]) in F
             ....:     for i in range(2,5) for letter in ['A','B','D'])
             True
             sage: all(CoxeterGroup(['E',i]) in F for i in range(6,9))
             True
             sage: CoxeterGroup(['F',4]).category()
-            Category of finite irreducible coxeter groups
+            Category of finite irreducible Coxeter groups
             sage: CoxeterGroup(['G',2]).category()
-            Category of finite irreducible coxeter groups
+            Category of finite irreducible Coxeter groups
             sage: all(CoxeterGroup(['H',i]) in F for i in range(3,5))
             True
             sage: all(CoxeterGroup(['I',i]) in F for i in range(2,5))

src/sage/groups/perm_gps/permgroup_named.py

@@ -640,7 +640,7 @@ def algebra(self, base_ring, category=None):
         We illustrate the choice of the category::
 
             sage: A.category()                                                          # needs sage.combinat
-            Join of Category of coxeter group algebras over Rational Field
+            Join of Category of Coxeter group algebras over Rational Field
                 and Category of finite group algebras over Rational Field
                 and Category of finite dimensional cellular algebras with basis
                      over Rational Field