Use Rachana instead of Meera for Malayalam

Meera is a sans-serif font for Malayalam. that should be substituted for serif.
2 jobs for <span class="ref-name">malayalam-serif</span> in 6 minutes and 39 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #43237
shared-build

00:06:05

passed #43238
static-build

00:06:39