MAINT: Remove nickname from polynomial classes. (gh-16589)

* MAINT: Remove nickname from polynomial classes.

The convenience classes derived from ABCPolyBase had a nickname
attribute that was only used internally in the previous
implementation of __str__. After the overhaul of __str__ in #15666,
this attr is no longer used.

* DOC: Add release note.

Add release note to notify users of removal of the abstract
property, and highlight users that may be affected by the
change.

* DOC: fixed rST in release note

7 files changed, 0 insertions, 11 deletions

diff --git a/numpy/polynomial/_polybase.py b/numpy/polynomial/_polybase.py
index b5341ba37..f4a67a222 100644
--- a/numpy/polynomial/_polybase.py
+++ b/numpy/polynomial/_polybase.py
@@ -111,11 +111,6 @@ class ABCPolyBase(abc.ABC):
 
     @property
     @abc.abstractmethod
-    def nickname(self):
-        pass
-
-    @property
-    @abc.abstractmethod
     def basis_name(self):
         pass
 
diff --git a/numpy/polynomial/chebyshev.py b/numpy/polynomial/chebyshev.py
index 431617414..d99fd98f5 100644
--- a/numpy/polynomial/chebyshev.py
+++ b/numpy/polynomial/chebyshev.py
@@ -2058,7 +2058,6 @@ class Chebyshev(ABCPolyBase):
         return cls(coef, domain=domain)
 
     # Virtual properties
-    nickname = 'cheb'
     domain = np.array(chebdomain)
     window = np.array(chebdomain)
     basis_name = 'T'
diff --git a/numpy/polynomial/hermite.py b/numpy/polynomial/hermite.py
index 487d8dfdb..280cad39e 100644
--- a/numpy/polynomial/hermite.py
+++ b/numpy/polynomial/hermite.py
@@ -1675,7 +1675,6 @@ class Hermite(ABCPolyBase):
     _fromroots = staticmethod(hermfromroots)
 
     # Virtual properties
-    nickname = 'herm'
     domain = np.array(hermdomain)
     window = np.array(hermdomain)
     basis_name = 'H'
diff --git a/numpy/polynomial/hermite_e.py b/numpy/polynomial/hermite_e.py
index cbec15184..9b3b25105 100644
--- a/numpy/polynomial/hermite_e.py
+++ b/numpy/polynomial/hermite_e.py
@@ -1669,7 +1669,6 @@ class HermiteE(ABCPolyBase):
     _fromroots = staticmethod(hermefromroots)
 
     # Virtual properties
-    nickname = 'herme'
     domain = np.array(hermedomain)
     window = np.array(hermedomain)
     basis_name = 'He'
diff --git a/numpy/polynomial/laguerre.py b/numpy/polynomial/laguerre.py
index 5b66d943e..b3f795b4f 100644
--- a/numpy/polynomial/laguerre.py
+++ b/numpy/polynomial/laguerre.py
@@ -1626,7 +1626,6 @@ class Laguerre(ABCPolyBase):
     _fromroots = staticmethod(lagfromroots)
 
     # Virtual properties
-    nickname = 'lag'
     domain = np.array(lagdomain)
     window = np.array(lagdomain)
     basis_name = 'L'
diff --git a/numpy/polynomial/legendre.py b/numpy/polynomial/legendre.py
index 47e47a7b6..7b5b665f2 100644
--- a/numpy/polynomial/legendre.py
+++ b/numpy/polynomial/legendre.py
@@ -1642,7 +1642,6 @@ class Legendre(ABCPolyBase):
     _fromroots = staticmethod(legfromroots)
 
     # Virtual properties
-    nickname = 'leg'
     domain = np.array(legdomain)
     window = np.array(legdomain)
     basis_name = 'P'
diff --git a/numpy/polynomial/polynomial.py b/numpy/polynomial/polynomial.py
index 97f1e7dc0..83693441f 100644
--- a/numpy/polynomial/polynomial.py
+++ b/numpy/polynomial/polynomial.py
@@ -1490,7 +1490,6 @@ class Polynomial(ABCPolyBase):
     _fromroots = staticmethod(polyfromroots)
 
     # Virtual properties
-    nickname = 'poly'
     domain = np.array(polydomain)
     window = np.array(polydomain)
     basis_name = None