patch 8.2.3970: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more errors to errors.h.
diff --git a/src/eval.c b/src/eval.c
index 6094b60..fa3941c 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -856,7 +856,7 @@
 	if (unlet && !VIM_ISWHITE(*p) && !ends_excmd(*p)
 						    && *p != '[' && *p != '.')
 	{
-	    semsg(_(e_trailing_arg), p);
+	    semsg(_(e_trailing_characters_str), p);
 	    return NULL;
 	}
 
@@ -2269,7 +2269,7 @@
 		&& (!in_vim9script() || !vim9_bad_comment(p)))
 	{
 	    if (end_error)
-		semsg(_(e_trailing_arg), p);
+		semsg(_(e_trailing_characters_str), p);
 	    else
 		semsg(_(e_invalid_expression_str), arg);
 	}
@@ -4129,7 +4129,7 @@
 	case VAR_FLOAT:
 #ifdef FEAT_FLOAT
 	    if (verbose)
-		emsg(_(e_float_as_string));
+		emsg(_(e_using_float_as_string));
 	    return FAIL;
 #endif
 	case VAR_BOOL: