Multi ticket typo fixes

[karbates]

• FHIR-33525: Swapped CDC link on COVID-19 for WHO link in Scope section of index.md
• FHIR-33529: Fixed typo, from "steam" to "stream" on contact.md
• FHIR-33597: Swapped colon for period after "US profiles of Patient" and added "to" after two instances of "SHALL conform" in patient.md
• FHIR-33598: Changed [] to () around VaccineTypeSNOMED so they render as a link in vaccination.md

[p9g]

For convenience https://jira.hl7.org/browse/FHIR-33525 https://jira.hl7.org/browse/FHIR-33529 https://jira.hl7.org/browse/FHIR-33597 https://jira.hl7.org/browse/FHIR-33598

[p9g]

The fix for FHIR-33598 does not work. See https://build.fhir.org/ig/HL7/fhir-shc-vaccination-ig/branches/multi-ticket-typo-fixes/vaccination.html This is related to https://github.com/HL7/fhir-shc-vaccination-ig/blob/master/examples/byCodeSystem/README.md that has a column for Value Set which has terms like VaccineTypeSNOMED which are not used in the IG.

[p9g]

https://github.com/HL7/fhir-shc-vaccination-ig/pull/192 has applied some of these same changes

[masnick]

Covered by #192