math: fix typos in Bessel function docs
math: fix typos in Bessel function docs

While we're at it, also document Yn(0, 0) = -Inf for completeness.

Fixes #18823.

Change-Id: Ib6db68f76d29cc2373c12ebdf3fab129cac8c167
Reviewed-on: https://go-review.googlesource.com/35970
Reviewed-by: Josh Bleecher Snyder <cdc248cc4d32e4fbfe04e45228163bcecd48a0b9@gmail.com>
Run-TryBot: Josh Bleecher Snyder <cdc248cc4d32e4fbfe04e45228163bcecd48a0b9@gmail.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

codestation/go,CAFxX/go,akutz/go,cloudflare/go,ImJasonH/go,cloudflare/go,Cofyc/go,nawawi/go,polyverse-security/go,josharian/go,josharian/go,polyverse-security/go,cloudflare/go,josharian/go,nawawi/go,Cofyc/go,vsekhar/elastic-go,christopher-henderson/Go,polyverse-security/go,akutz/go,CAFxX/go,codestation/go,josharian/go,linux-on-ibm-z/go,derekmarcotte/go,derekmarcotte/go,codestation/go,nawawi/go,polyverse-security/go,polyverse-security/go,nawawi/go,Cofyc/go,ImJasonH/go,codestation/go,ImJasonH/go,akutz/go,Cofyc/go,cloudflare/go,akutz/go,linux-on-ibm-z/go,codestation/go,nawawi/go,vsekhar/elastic-go,derekmarcotte/go,golang/go,josharian/go,CAFxX/go,linux-on-ibm-z/go,nawawi/go,vsekhar/elastic-go,nawawi/go,akutz/go,josharian/go,codestation/go,linux-on-ibm-z/go,derekmarcotte/go,golang/go,cloudflare/go,CAFxX/go,Cofyc/go,akutz/go,golang/go,linux-on-ibm-z/go,polyverse-security/go,ImJasonH/go,Cofyc/go,akutz/go,josharian/go,vsekhar/elastic-go,CAFxX/go,CAFxX/go,golang/go,CAFxX/go,linux-on-ibm-z/go,ImJasonH/go,cloudflare/go,Cofyc/go,akutz/go,CAFxX/go,derekmarcotte/go,ImJasonH/go,golang/go,derekmarcotte/go,vsekhar/elastic-go,nawawi/go,polyverse-security/go,golang/go,golang/go,cloudflare/go,cloudflare/go,josharian/go,codestation/go,golang/go,vsekhar/elastic-go,polyverse-security/go,derekmarcotte/go,linux-on-ibm-z/go,vsekhar/elastic-go,ImJasonH/go,ImJasonH/go,vsekhar/elastic-go,linux-on-ibm-z/go,Cofyc/go,codestation/go,derekmarcotte/go