ci: enable checks for missing Go documentation

Checks for missing Go documentation used to be covered by the now
defunct project `golint`. Revive is a replacement for golint that is
used by `golangci-lint`. However, `golangci-lint` disables checks for
missing Go documentation by default[0]. The only way to re-enable them
is apparently to suppress golangci-lint's default rules, which is what
this commit does. Rules that triggered false-positive on this codebase
have been manually added. The list of default exclude rules can be found
by running `golangci-lint run --help`.

[0]: golangci/golangci-lint#456

Signed-off-by: Robin Hahling <robin.hahling@gw-computing.net>

.golangci.yml

@@ -34,6 +34,10 @@ linters-settings:
     go: "1.16"
 
 issues:
+  exclude-use-default: false # default rules exclude doc comments check :(
+  exclude:
+    - (G104|G307) # EXC0008 gosec: Duplicated errcheck checks
+
   exclude-rules:
     - linters: [staticcheck]
       text: "SA1019" # deprecated methods