patch 8.2.3917: the eval.txt help file is way too big

Problem:    The eval.txt help file is way too big.
Solution:   Move the builtin function details to a separate file.

runtime/doc/Makefile

@@ -16,6 +16,7 @@ include ../../src/auto/config.mk
 DOCS = \
 	arabic.txt \
 	autocmd.txt \
+	builtin.txt \
 	change.txt \
 	channel.txt \
 	cmdline.txt \
@@ -161,6 +162,7 @@ DOCS = \
 HTMLS = \
 	arabic.html \
 	autocmd.html \
+	builtin.html \
 	change.html \
 	channel.html \
 	cmdline.html \

runtime/doc/help.txt

@@ -136,6 +136,7 @@ Advanced editing ~
 |diff.txt|	working with two to eight versions of the same file
 |autocmd.txt|	automatically executing commands on an event
 |eval.txt|	expression evaluation, conditional commands
+|builtin.txt|	builtin functions
 |channel.txt|	Jobs, Channels, inter-process communication
 |fold.txt|	hide (fold) ranges of lines
 

runtime/doc/remote.txt

@@ -143,7 +143,7 @@ You can not put options there!
 FUNCTIONS
 								*E240* *E573*
 There are a number of Vim functions for scripting the command server.  See
-the description in |eval.txt| or use CTRL-] on the function name to jump to
+the description in |builtin.txt| or use CTRL-] on the function name to jump to
 the full explanation.
 
     synopsis				     explanation ~

src/version.c

@@ -749,6 +749,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3917,
 /**/
     3916,
 /**/