Consistently avoid infix syntax in the GSG and reinstantiate dlint (#5483)

We avoided infix syntax here for `elem` but still used it for
`notElem` which doesn’t make much sense. Also we lost the config to
disable the lint when integrating the example in this repo. This
resulted in our own code producing a lint which is obviously a bad
idea.

side note: I think this lint does make sense once you
are familiar with the syntax and I feel slightly bad about disabling
more and more lints so for now I’m keeping it in the config.

changelog_begin
changelog_end

docs/source/getting-started/code/daml-after/User.daml

@@ -18,7 +18,7 @@ template User with
       controller username
       do
         assertMsg "You cannot follow yourself" (userToFollow /= username)
-        assertMsg "You cannot follow the same user twice" (userToFollow `notElem` following)
+        assertMsg "You cannot follow the same user twice" (notElem userToFollow following)
         archive self
         create this with following = userToFollow :: following
 

templates/BUILD.bazel

@@ -30,6 +30,16 @@ genrule(
             # use default .gitignore and .dlint.yaml if they don't exist in the template
             cp -n $$SRC/default-gitignore $$OUT/$$d/.gitignore
             cp -n $$SRC/default-dlint-yaml $$OUT/$$d/.dlint.yaml
+            # We avoid introducing infix syntax in the GSG so we disable
+            # the lint there.
+            if [ "$$d" = "create-daml-app" ]; then
+              cat >> $$OUT/$$d/.dlint.yaml <<EOF
+
+# This rule is enabled by default but we avoid
+# infix syntax here to keep things simple.
+- ignore: {name: Use infix }
+EOF
+            fi
         done
 
         ## special cases we should work to remove

templates/create-daml-app/daml/User.daml

@@ -21,7 +21,7 @@ template User with
       controller username
       do
         assertMsg "You cannot follow yourself" (userToFollow /= username)
-        assertMsg "You cannot follow the same user twice" (userToFollow `notElem` following)
+        assertMsg "You cannot follow the same user twice" (notElem userToFollow following)
         archive self
         create this with following = userToFollow :: following
     -- FOLLOW_END