Disable Pike target language

Clean up to disable target languages that have been neglected/not functional.
Target language be fully deleted in SWIG 4.1 unless a new maintainer brings
it up to an acceptable status (experimental or supported).

Issue #1447

Doc/Manual/Preprocessor.html

@@ -126,7 +126,6 @@ SWIGOCTAVE                      Defined when using Octave
 SWIGPERL                        Defined when using Perl
 SWIGPHP                         Defined when using PHP (any version)
 SWIGPHP7                        Defined when using PHP7
-SWIGPIKE                        Defined when using Pike
 SWIGPYTHON                      Defined when using Python
 SWIGR                           Defined when using R
 SWIGRUBY                        Defined when using Ruby

Doc/Manual/SWIG.html

@@ -134,7 +134,6 @@ Supported Target Language Options
      -octave         - Generate Octave wrappers
      -perl           - Generate Perl wrappers
      -php7           - Generate PHP7 wrappers
-     -pike           - Generate Pike wrappers
      -python         - Generate Python wrappers
      -r              - Generate R (aka GNU S) wrappers
      -ruby           - Generate Ruby wrappers

Doc/Manual/Sections.html

@@ -55,7 +55,6 @@ Last update : SWIG-4.0.0 (in progress)
 <li><a href="Octave.html#Octave">Octave support</a></li>
 <li><a href="Perl5.html#Perl5">Perl5 support</a></li>
 <li><a href="Php.html#Php">PHP support</a></li>
-<li><a href="Pike.html#Pike">Pike support</a></li>
 <li><a href="Python.html#Python">Python support</a></li>
 <li><a href="R.html#R">R support</a></li>
 <li><a href="Ruby.html#Ruby">Ruby support</a></li>

Doc/Manual/chapters

@@ -33,7 +33,6 @@ Ocaml.html
 Octave.html
 Perl5.html
 Php.html
-Pike.html
 Python.html
 R.html
 Ruby.html