Fix incorrect regex on Person.name field

[mattnworb]

The example regular expression introduced in 10eb9db does not seem to work as intended, due to nesting a negated range inside another range:

❯ jshell --class-path ~/.m2/repository/com/google/re2j/re2j/1.7/re2j-1.7.jar
|  Welcome to JShell -- Version 17.0.9
|  For an introduction type: /help intro

jshell> com.google.re2j.Pattern p = com.google.re2j.Pattern.compile("^[^[0-9]A-Za-z]+( [^[0-9]A-Za-z]+)*$");
p ==> ^[^[0-9]A-Za-z]+( [^[0-9]A-Za-z]+)*$

jshell> p.matches(pattern, "Protocol Buffers");
$4 ==> false

jshell> p.matches(pattern, "Matt Brown");
$5 ==> false

The nesting of ranges in the example is also redundant - if you are going to specify that only [A-Za-z] is valid than including [^0-9]` in that range is not necessary.

This commit fixes the example regular expression to match the example "name" mentioned later in the README.

[CLAassistant]

All committers have signed the CLA.

[rodaine]

Hey, @mattnworb, and thanks for the patch!

Hm, looks like at some point it was made inconsistent with the regex that was originally in the readme: '^[^\d\s]+( [^\d\s]+)*$'. I'm guessing to avoid having to show the gnarly escaping that would have required. Can you make line 61 consistent with your change as well?

[mattnworb]

@rodaine ah good catch, I believe the inconsistency with line 61 was introduced in 10eb9db. I'll push a commit to make them consistent

[mattnworb]

noticed an occurrence of the regex used in python/README.md too

[rodaine]

Looks good! Once you sign the CLA we can get this merged 😁

[mattnworb]

done, thanks!

[rodaine]

Thanks again! 😁