Issue #20998: Fixed re.fullmatch() of repeated single character pattern

with ignore case.  Original patch by Matthew Barnett.

diff --cc Misc/NEWS
index e815e0eb5d06107fce31060952c4c566ce0d0684,e2836a1cea4d66b5f65db0832e8d637088e7169c..2412c4829e671aaefa9b77de9b73e5a934ee1ec8
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -84,30 -90,6 +84,33 @@@ Core and Builtin
  Library
  -------
  
++- Issue #20998: Fixed re.fullmatch() of repeated single character pattern
++  with ignore case.  Original patch by Matthew Barnett.
++
 +- Issue #21075: fileinput.FileInput now reads bytes from standard stream if
 +  binary mode is specified.  Patch by Sam Kimbrel.
 +
 +- Issue #19775: Add a samefile() method to pathlib Path objects.  Initial
 +  patch by Vajrasky Kok.
 +
 +- Issue #21398: Fix an unicode error in the pydoc pager when the documentation
 +  contains characters not encodable to the stdout encoding.
 +
 +- Issue #16531: ipaddress.IPv4Network and ipaddress.IPv6Network now accept
 +  an (address, netmask) tuple argument, so as to easily construct network
 +  objects from existing addresses.
 +
 +- Issue #21156: importlib.abc.InspectLoader.source_to_code() is now a
 +  staticmethod.
 +
 +- Issue #21424: Simplified and optimized heaqp.nlargest() and nmsmallest()
 +  to make fewer tuple comparisons.
 +
 +- Issue #21396: Fix TextIOWrapper(..., write_through=True) to not force a
 +  flush() on the underlying binary stream.  Patch by akira.
 +
 +- Issue #18314: Unlink now removes junctions on Windows. Patch by Kim Gräsman
 +
  - Issue #21088: Bugfix for curses.window.addch() regression in 3.4.0.
    In porting to Argument Clinic, the first two arguments were reversed.