patch 8.2.0532: cannot use simplify() as a method

Problem:    Cannot use simplify() as a method.
Solution:   Add FEARG_1. (closes #5996)

src/evalfunc.c

@@ -837,7 +837,7 @@ static funcentry_T global_functions[] =
     {"sign_undefine",	0, 1, FEARG_1,	  ret_number,	SIGN_FUNC(f_sign_undefine)},
     {"sign_unplace",	1, 2, FEARG_1,	  ret_number,	SIGN_FUNC(f_sign_unplace)},
     {"sign_unplacelist", 1, 2, FEARG_1,	  ret_list_number, SIGN_FUNC(f_sign_unplacelist)},
-    {"simplify",	1, 1, 0,	  ret_string,	f_simplify},
+    {"simplify",	1, 1, FEARG_1,	  ret_string,	f_simplify},
     {"sin",		1, 1, FEARG_1,	  ret_float,	FLOAT_FUNC(f_sin)},
     {"sinh",		1, 1, FEARG_1,	  ret_float,	FLOAT_FUNC(f_sinh)},
     {"sort",		1, 3, FEARG_1,	  ret_list_any,	f_sort},

src/testdir/test_functions.vim

@@ -450,7 +450,7 @@ func Test_simplify()
   call assert_equal('/',           simplify('/.'))
   call assert_equal('/',           simplify('/..'))
   call assert_equal('/...',        simplify('/...'))
-  call assert_equal('./dir/file',  simplify('./dir/file'))
+  call assert_equal('./dir/file',  './dir/file'->simplify())
   call assert_equal('./dir/file',  simplify('.///dir//file'))
   call assert_equal('./dir/file',  simplify('./dir/./file'))
   call assert_equal('./file',      simplify('./dir/../file'))

src/version.c

@@ -738,6 +738,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    532,
 /**/
     531,
 /**/