REPOST: Better error messages for "read -c" / "read -l"

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

This previously appeared in workers/32100 but I hate ChangeLog entries that
are out of chronological article number order.

diff --git a/Src/Zle/compctl.c b/Src/Zle/compctl.c
index ab1857c..2563095 100644
--- a/Src/Zle/compctl.c
+++ b/Src/Zle/compctl.c
@@ -193,7 +193,7 @@ compctlread(char *name, char **args, Options ops, char *reply)
 
     /* only allowed to be called for completion */
     if (!incompctlfunc) {
-	zwarnnam(name, "option valid only in functions called for completion");
+	zwarnnam(name, "option valid only in functions called via compctl");
 	return 1;
     }
 
diff --git a/Src/init.c b/Src/init.c
index f5aae71..bd871cb 100644
--- a/Src/init.c
+++ b/Src/init.c
@@ -1535,7 +1535,7 @@ mod_export CompctlReadFn compctlreadptr = fallback_compctlread;
 mod_export int
 fallback_compctlread(char *name, UNUSED(char **args), UNUSED(Options ops), UNUSED(char *reply))
 {
-    zwarnnam(name, "option valid only in functions called from completion");
+    zwarnnam(name, "no loaded module provides read for completion context");
     return 1;
 }