patch 8.1.2062: the mouse code is spread out

Problem:    The mouse code is spread out.
Solution:   Move all the mouse code to mouse.c. (Yegappan Lakshmanan,
            closes #4959)
diff --git a/src/proto/normal.pro b/src/proto/normal.pro
index dd62226..3a0a6e0 100644
--- a/src/proto/normal.pro
+++ b/src/proto/normal.pro
@@ -2,13 +2,15 @@
 void init_normal_cmds(void);
 void normal_cmd(oparg_T *oap, int toplevel);
 void do_pending_operator(cmdarg_T *cap, int old_col, int gui_yank);
-int do_mouse(oparg_T *oap, int c, int dir, long count, int fixindent);
 void check_visual_highlight(void);
 void end_visual_mode(void);
 void reset_VIsual_and_resel(void);
 void reset_VIsual(void);
 int find_ident_under_cursor(char_u **text, int find_type);
 int find_ident_at_pos(win_T *wp, linenr_T lnum, colnr_T startcol, char_u **text, int *textcol, int find_type);
+void prep_redo(int regname, long, int, int, int, int, int);
+void clearop(oparg_T *oap);
+void clearopbeep(oparg_T *oap);
 void clear_showcmd(void);
 int add_to_showcmd(int c);
 void add_to_showcmd_c(int c);
@@ -17,6 +19,7 @@
 void do_check_scrollbind(int check);
 void check_scrollbind(linenr_T topline_diff, long leftcol_diff);
 int find_decl(char_u *ptr, int len, int locally, int thisblock, int flags_arg);
+void nv_scroll_line(cmdarg_T *cap);
 void scroll_redraw(int up, long count);
 void handle_tabmenu(void);
 void do_nv_ident(int c1, int c2);