Implement type command (#19944)

* Implement type command

- this will be mapped to textDocument/typeDefinition in LSP protocol. It will be
very useful for `nim` in particular because typically most of the time the type
is inferred.

* Update nimsuggest/nimsuggest.nim

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

nimsuggest/tests/tv3_typeDefinition.nim

@@ -0,0 +1,32 @@
+# tests v3
+
+type
+  Foo* = ref object of RootObj
+    bar*: string
+
+proc test(ff: Foo) =
+  echo f#[!]#f.bar
+
+type
+  Fo#[!]#o2* = ref object of RootObj
+
+type
+  FooGeneric[T] = ref object of RootObj
+    bar*: T
+
+let fooGeneric = FooGeneric[string]()
+echo fo#[!]#oGeneric.bar
+
+# bad type
+echo unde#[!]#fined
+
+discard """
+$nimsuggest --v3 --tester $file
+>type $1
+type	skType	tv3_typeDefinition.Foo	Foo	$file	4	2	""	100
+>type $2
+type	skType	tv3_typeDefinition.Foo2	Foo2	$file	11	2	""	100
+>type $3
+type	skType	tv3_typeDefinition.FooGeneric	FooGeneric	$file	14	2	""	100
+>type $4
+"""