patch 8.1.2004: more functions can be used as methods

Problem:    More functions can be used as methods.
Solution:   Make various functions usable as a method.
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 2461b6c..19922da 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -715,38 +715,38 @@
     {"sort",		1, 3, FEARG_1,	  f_sort},
 #ifdef FEAT_SOUND
     {"sound_clear",	0, 0, 0,	  f_sound_clear},
-    {"sound_playevent",	1, 2, 0,	  f_sound_playevent},
-    {"sound_playfile",	1, 2, 0,	  f_sound_playfile},
-    {"sound_stop",	1, 1, 0,	  f_sound_stop},
+    {"sound_playevent",	1, 2, FEARG_1,	  f_sound_playevent},
+    {"sound_playfile",	1, 2, FEARG_1,	  f_sound_playfile},
+    {"sound_stop",	1, 1, FEARG_1,	  f_sound_stop},
 #endif
-    {"soundfold",	1, 1, 0,	  f_soundfold},
-    {"spellbadword",	0, 1, 0,	  f_spellbadword},
-    {"spellsuggest",	1, 3, 0,	  f_spellsuggest},
+    {"soundfold",	1, 1, FEARG_1,	  f_soundfold},
+    {"spellbadword",	0, 1, FEARG_1,	  f_spellbadword},
+    {"spellsuggest",	1, 3, FEARG_1,	  f_spellsuggest},
     {"split",		1, 3, FEARG_1,	  f_split},
 #ifdef FEAT_FLOAT
     {"sqrt",		1, 1, FEARG_1,	  f_sqrt},
     {"str2float",	1, 1, FEARG_1,	  f_str2float},
 #endif
     {"str2list",	1, 2, FEARG_1,	  f_str2list},
-    {"str2nr",		1, 2, 0,	  f_str2nr},
-    {"strcharpart",	2, 3, 0,	  f_strcharpart},
-    {"strchars",	1, 2, 0,	  f_strchars},
-    {"strdisplaywidth",	1, 2, 0,	  f_strdisplaywidth},
+    {"str2nr",		1, 2, FEARG_1,	  f_str2nr},
+    {"strcharpart",	2, 3, FEARG_1,	  f_strcharpart},
+    {"strchars",	1, 2, FEARG_1,	  f_strchars},
+    {"strdisplaywidth",	1, 2, FEARG_1,	  f_strdisplaywidth},
 #ifdef HAVE_STRFTIME
-    {"strftime",	1, 2, 0,	  f_strftime},
+    {"strftime",	1, 2, FEARG_1,	  f_strftime},
 #endif
-    {"strgetchar",	2, 2, 0,	  f_strgetchar},
-    {"stridx",		2, 3, 0,	  f_stridx},
+    {"strgetchar",	2, 2, FEARG_1,	  f_strgetchar},
+    {"stridx",		2, 3, FEARG_1,	  f_stridx},
     {"string",		1, 1, FEARG_1,	  f_string},
     {"strlen",		1, 1, FEARG_1,	  f_strlen},
-    {"strpart",		2, 3, 0,	  f_strpart},
-    {"strridx",		2, 3, 0,	  f_strridx},
+    {"strpart",		2, 3, FEARG_1,	  f_strpart},
+    {"strridx",		2, 3, FEARG_1,	  f_strridx},
     {"strtrans",	1, 1, FEARG_1,	  f_strtrans},
     {"strwidth",	1, 1, FEARG_1,	  f_strwidth},
-    {"submatch",	1, 2, 0,	  f_submatch},
+    {"submatch",	1, 2, FEARG_1,	  f_submatch},
     {"substitute",	4, 4, FEARG_1,	  f_substitute},
-    {"swapinfo",	1, 1, 0,	  f_swapinfo},
-    {"swapname",	1, 1, 0,	  f_swapname},
+    {"swapinfo",	1, 1, FEARG_1,	  f_swapinfo},
+    {"swapname",	1, 1, FEARG_1,	  f_swapname},
     {"synID",		3, 3, 0,	  f_synID},
     {"synIDattr",	2, 3, FEARG_1,	  f_synIDattr},
     {"synIDtrans",	1, 1, FEARG_1,	  f_synIDtrans},