Add LinearVerbosity type constraint

Author: RomeoV

src/common.jl

@@ -105,7 +105,7 @@ The cache automatically tracks when matrix `A` or parameters `p` change by setti
 appropriate freshness flags. When `solve!` is called, stale cache entries are automatically
 recomputed as needed.
 """
-mutable struct LinearCache{TA, Tb, Tu, Tp, Talg, Tc, Tl, Tr, Ttol, Tlv, issq, S}
+mutable struct LinearCache{TA, Tb, Tu, Tp, Talg, Tc, Tl, Tr, Ttol, Tlv <: LinearVerbosity, issq, S}
     A::TA
     b::Tb
     u::Tu