DOC: add char.isalpha example

Author: luxedo

numpy/_core/code_generators/ufunc_docstrings.py

@@ -4373,6 +4373,17 @@ def add_newdoc(place, name, doc):
     --------
     str.isalpha
 
+    Examples
+    --------
+    >>> np.char.isalpha(["yes", "alpha"])
+    array([ True,  True])
+    >>> np.char.isalpha(["not", "\x00", "alpha"])
+    array([ True, False,  True])
+    >>> np.char.isalpha(["n0t", "4lpha"])
+    array([ False, False])
+    >>> np.char.isalpha(bytes([0x61, 0x6c, 0x70, 0x68, 0x61]))
+    np.True_
+
     """)
 
 add_newdoc('numpy._core.umath', 'isdigit',