lint: enable custom linters from go-lint project

.golangci.yaml

@@ -20,7 +20,20 @@ linters:
     - whitespace
     - wrapcheck
 
+    # Shared custom linters from ../go-lint.
+    - ifinit
+    - boolnames
+
   settings:
+    custom:
+      ifinit:
+        type: module
+        description: if-statement init clauses must be on a single line
+      boolnames:
+        type: module
+        description: boolean variables and functions should use is, has, was, and similar prefixes
+        settings:
+          allowed_prefixes: ["is", "has", "can", "was", "should"]
     depguard:
       rules:
         main: