patch 8.1.2081: the spell.c file is too big

Problem:    The spell.c file is too big.
Solution:   Move the code for spell suggestions to a separate file. (Yegappan
            Lakshmanan, closes #4988)
diff --git a/src/Makefile b/src/Makefile
index 9462404..0f949a8 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1654,6 +1654,7 @@
 	sound.c \
 	spell.c \
 	spellfile.c \
+	spellsuggest.c \
 	syntax.c \
 	tag.c \
 	term.c \
@@ -1789,6 +1790,7 @@
 	objects/sound.o \
 	objects/spell.o \
 	objects/spellfile.o \
+	objects/spellsuggest.o \
 	objects/syntax.o \
 	objects/tag.o \
 	objects/term.o \
@@ -1949,6 +1951,7 @@
 	sound.pro \
 	spell.pro \
 	spellfile.pro \
+	spellsuggest.pro \
 	syntax.pro \
 	tag.pro \
 	term.pro \
@@ -3386,6 +3389,9 @@
 objects/spellfile.o: spellfile.c
 	$(CCC) -o $@ spellfile.c
 
+objects/spellsuggest.o: spellsuggest.c
+	$(CCC) -o $@ spellsuggest.c
+
 objects/syntax.o: syntax.c
 	$(CCC) -o $@ syntax.c
 
@@ -3881,6 +3887,10 @@
  os_unix.h auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
  proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \
  proto.h globals.h
+objects/spellsuggest.o: spellsuggest.c vim.h protodef.h auto/config.h feature.h \
+ os_unix.h auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
+ proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \
+ proto.h globals.h
 objects/syntax.o: syntax.c vim.h protodef.h auto/config.h feature.h os_unix.h \
  auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
  proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \