Add Lsv4 and related VM series

Author: johndowns

articles/reliability/availability-service-by-category.md

@@ -150,6 +150,7 @@ Azure services are presented in the following lists by category. Note that some
 - Virtual Machines: HCv1-series
 - Virtual Machines: Lsv2-series
 - Virtual Machines: Lsv3-series
+- Virtual Machines: Lsv4, Lasv4, and Laosv4-series
 - Virtual Machines: Mv2-series
 - Virtual Machines: NCasT4_v3-series
 - Virtual Machines: NCv3-series