[bug-gawk] On uninitialized variables

[M]

Hello! When rereading the manual (v5.0.0), I noticed an inexact statement in 
Chapter 1:

1.5 A More Complex Example

"(This works because awk variables are automatically initialized to zero.)"

It's true only in a numeric context.
When used as strings, uninitialized variables are automatically initialized to 
an empty string.
Although this peculiarity is emphasised throughout the rest of the manual,
I think it would be useful to mention about it in the introduction chapter too 
(especially for novices).