feat(language-service): complete attributes on elements (#40032)

This commit adds attribute completion to the Language Service. It completes
from 3 sources:

1. inputs/outputs of directives currently present on the element
2. inputs/outputs/attributes of directives in scope for the element, that
   would become present if the input/output/attribute was added
3. DOM properties and attributes

We distinguish between completion of a property binding (`[foo|]`) and a
completion in an attribute context (`foo|`). For the latter, bindings to
the attribute are offered, as well as a property binding which adds the
square bracket notation.

To determine hypothetical matches (directives which would become present if
a binding is added), directives in scope are scanned and matched against a
hypothetical version of the element which has the attribute.

PR Close #40032

packages/language-service/ivy/BUILD.bazel

@@ -11,6 +11,7 @@ ts_library(
         "//packages/compiler-cli/src/ngtsc/core",
         "//packages/compiler-cli/src/ngtsc/core:api",
         "//packages/compiler-cli/src/ngtsc/file_system",
+        "//packages/compiler-cli/src/ngtsc/imports",
         "//packages/compiler-cli/src/ngtsc/incremental",
         "//packages/compiler-cli/src/ngtsc/metadata",
         "//packages/compiler-cli/src/ngtsc/reflection",