gh-97669: Move difflib examples to Doc/includes/ (#97964)

Remove diff.py and ndiff.py scripts of Tools/scripts/: move them to
Doc/includes/.

* diff.py and ndiff.py files are no longer executable. Remove also
  their shebang ("#!/usr/bin/env python3").
* Remove the -profile command from ndiff.py to simply the code.
* Remove ndiff.py copyright and history command. The Python
  documentation examples are distributed under the "Zero Clause BSD
  License".

Doc/includes/ndiff.py

@@ -0,0 +1,111 @@
+"""ndiff [-q] file1 file2
+    or
+ndiff (-r1 | -r2) < ndiff_output > file1_or_file2
+
+Print a human-friendly file difference report to stdout.  Both inter-
+and intra-line differences are noted.  In the second form, recreate file1
+(-r1) or file2 (-r2) on stdout, from an ndiff report on stdin.
+
+In the first form, if -q ("quiet") is not specified, the first two lines
+of output are
+
+-: file1
++: file2
+
+Each remaining line begins with a two-letter code:
+
+    "- "    line unique to file1
+    "+ "    line unique to file2
+    "  "    line common to both files
+    "? "    line not present in either input file
+
+Lines beginning with "? " attempt to guide the eye to intraline
+differences, and were not present in either input file.  These lines can be
+confusing if the source files contain tab characters.
+
+The first file can be recovered by retaining only lines that begin with
+"  " or "- ", and deleting those 2-character prefixes; use ndiff with -r1.
+
+The second file can be recovered similarly, but by retaining only "  " and
+"+ " lines; use ndiff with -r2; or, on Unix, the second file can be
+recovered by piping the output through
+
+    sed -n '/^[+ ] /s/^..//p'
+"""
+
+__version__ = 1, 7, 0
+
+import difflib, sys
+
+def fail(msg):
+    out = sys.stderr.write
+    out(msg + "\n\n")
+    out(__doc__)
+    return 0
+
+# open a file & return the file object; gripe and return 0 if it
+# couldn't be opened
+def fopen(fname):
+    try:
+        return open(fname)
+    except IOError as detail:
+        return fail("couldn't open " + fname + ": " + str(detail))
+
+# open two files & spray the diff to stdout; return false iff a problem
+def fcompare(f1name, f2name):
+    f1 = fopen(f1name)
+    f2 = fopen(f2name)
+    if not f1 or not f2:
+        return 0
+
+    a = f1.readlines(); f1.close()
+    b = f2.readlines(); f2.close()
+    for line in difflib.ndiff(a, b):
+        print(line, end=' ')
+
+    return 1
+
+# crack args (sys.argv[1:] is normal) & compare;
+# return false iff a problem
+
+def main(args):
+    import getopt
+    try:
+        opts, args = getopt.getopt(args, "qr:")
+    except getopt.error as detail:
+        return fail(str(detail))
+    noisy = 1
+    qseen = rseen = 0
+    for opt, val in opts:
+        if opt == "-q":
+            qseen = 1
+            noisy = 0
+        elif opt == "-r":
+            rseen = 1
+            whichfile = val
+    if qseen and rseen:
+        return fail("can't specify both -q and -r")
+    if rseen:
+        if args:
+            return fail("no args allowed with -r option")
+        if whichfile in ("1", "2"):
+            restore(whichfile)
+            return 1
+        return fail("-r value must be 1 or 2")
+    if len(args) != 2:
+        return fail("need 2 filename args")
+    f1name, f2name = args
+    if noisy:
+        print('-:', f1name)
+        print('+:', f2name)
+    return fcompare(f1name, f2name)
+
+# read ndiff output from stdin, and print file1 (which=='1') or
+# file2 (which=='2') to stdout
+
+def restore(which):
+    restored = difflib.restore(sys.stdin.readlines(), which)
+    sys.stdout.writelines(restored)
+
+if __name__ == '__main__':
+    main(sys.argv[1:])