apply cw patch by @chrisbra to fix #6234

runtime/doc/motion.txt

@@ -402,7 +402,8 @@ WORD before the fold.
 
 Special case: "cw" and "cW" are treated like "ce" and "cE" if the cursor is
 on a non-blank.  This is because "cw" is interpreted as change-word, and a
-word does not include the following white space.
+word does not include the following white space. This behavior can be
+adjusted via |cpo-_|.
 
 Another special case: When using the "w" motion in combination with an
 operator and the last word moved over is at the end of a line, the end of

runtime/doc/options.txt

@@ -1829,6 +1829,9 @@ A jump table for the options with a short description can be found at |Q_op|.
 			character, the cursor won't move. When not included,
 			the cursor would skip over it and jump to the
 			following occurrence.
+								*cpo-_*
+		_	When using "cw" on a word, do not include the
+			whitespace following the word in the motion.
 
 						*'cscopepathcomp'* *'cspc'*
 'cscopepathcomp' 'cspc'	number	(default 0)

src/nvim/normal.c

@@ -7193,8 +7193,10 @@ static void nv_wordcmd(cmdarg_T *cap)
       // Another strangeness: When standing on the end of a word "ce" will
       // change until the end of the next word, but "cw" will change only one
       // character!  This is done by setting "flag".
-      cap->oap->inclusive = true;
-      word_end = true;
+      if (vim_strchr(p_cpo, CPO_CHANGEW) != NULL) {
+          cap->oap->inclusive = true;
+          word_end = true;
+      }
       flag = true;
     }
   }

src/nvim/option_defs.h

@@ -129,9 +129,11 @@
 #define CPO_REGAPPEND   '>'     /* insert NL when appending to a register */
 #define CPO_SCOLON      ';'     /* using "," and ";" will skip over char if
                                  * cursor would not move */
-/* default values for Vim and Vi */
-#define CPO_VIM         "aABceFs"
-#define CPO_VI          "aAbBcCdDeEfFiIJkKlLmMnoOpPqrRsStuvWxXyZ$!%+<>;"
+#define CPO_CHANGEW     '_'     // do not special-case cw, it works as
+                                // expected
+// default values for Vim and Vi
+#define CPO_VIM         "aABceFs_"
+#define CPO_VI          "aAbBcCdDeEfFiIJkKlLmMnoOpPqrRsStuvWxXyZ$!%+<>;_"
 
 /* characters for p_ww option: */
 #define WW_ALL          "bshl<>[],~"