feat: Produce completion items with kind = Reference (#363)

Previously, no kind was provided, which made editors treat these completions like 'Text' completions.

The problem with text completions is that they can be disabled by users due to their noise. Which then leads to confusion as to why Marksman's completion doesn't work in neovim or something.

Example config recommendation: https://github.com/hrsh7th/nvim-cmp/blob/5dce1b778b85c717f6614e3f4da45e9f19f54435/doc/cmp.txt#L663

Possibly fixes: #204

Marksman/Compl.fs

@@ -389,6 +389,7 @@ module Completions =
                         Detail = Some(Doc.pathFromRoot doc |> RelPath.toSystem)
                         TextEdit = Some(First textEdit)
                         FilterText = Some filterText
+                        Kind = Some CompletionItemKind.Reference
                 }
             | Some _ ->
                 let newText = targetLink
@@ -404,6 +405,7 @@ module Completions =
                         Detail = Some(Doc.pathFromRoot doc |> RelPath.toSystem)
                         TextEdit = Some(First textEdit)
                         FilterText = Some targetName
+                        Kind = Some CompletionItemKind.Reference
                 }
         | _ -> None
 
@@ -435,6 +437,7 @@ module Completions =
                 CompletionItem.Create(completionHeading) with
                     TextEdit = Some(First textEdit)
                     FilterText = Some newText
+                    Kind = Some CompletionItemKind.Reference
             }
         | _ -> None
 
@@ -480,6 +483,7 @@ module Completions =
                     Detail = Some(Doc.pathFromRoot doc |> RelPath.toSystem)
                     TextEdit = Some(First textEdit)
                     FilterText = Some filterText
+                    Kind = Some CompletionItemKind.Reference
             }
         | _ -> None
 
@@ -517,6 +521,7 @@ module Completions =
                     Documentation = MdLinkDef.urlContent def |> Documentation.String |> Some
                     TextEdit = Some(First textEdit)
                     FilterText = Some newText
+                    Kind = Some CompletionItemKind.Reference
             }
 
     let inlineDoc (pos: Position) (compl: Completable) (doc: Doc) : option<CompletionItem> =
@@ -533,6 +538,7 @@ module Completions =
                     Detail = detail
                     TextEdit =
                         Some(First { Range = Range.Mk(pos, pos); NewText = targetPathEncoded })
+                    Kind = Some CompletionItemKind.Reference
             }
         | E(ML { data = MdLink.IL(_, Some url, _) }) ->
             match Url.ofUrlNode url with
@@ -541,6 +547,7 @@ module Completions =
                     CompletionItem.Create(targetPath) with
                         Detail = detail
                         TextEdit = Some(First { Range = url.range; NewText = targetPathEncoded })
+                        Kind = Some CompletionItemKind.Reference
                 }
             | _ -> None
         | PE(PartialElement.InlineLink(Some _text, path, Some _anchor, _range)) ->
@@ -553,6 +560,7 @@ module Completions =
                 CompletionItem.Create(targetPath) with
                     Detail = detail
                     TextEdit = Some(First { Range = range; NewText = targetPathEncoded })
+                    Kind = Some CompletionItemKind.Reference
             }
         | PE(PartialElement.InlineLink(Some text, _path, None, range)) ->
             let newText =
@@ -563,6 +571,7 @@ module Completions =
                     Detail = detail
                     TextEdit = Some(First { Range = range; NewText = newText })
                     FilterText = Some newText
+                    Kind = Some CompletionItemKind.Reference
             }
         | _ -> None
 
@@ -585,6 +594,7 @@ module Completions =
                     CompletionItem.Create(completionHeading) with
                         TextEdit = Some(First { Range = anchor.range; NewText = newText })
                         FilterText = Some newText
+                        Kind = Some CompletionItemKind.Reference
                 }
             | _ -> None
         | PE(PartialElement.InlineLink(Some text, None, Some _anchor, range)) ->
@@ -594,6 +604,7 @@ module Completions =
                 CompletionItem.Create(completionHeading) with
                     TextEdit = Some(First { Range = range; NewText = newText })
                     FilterText = Some newText
+                    Kind = Some CompletionItemKind.Reference
             }
         | _ -> None
 
@@ -624,6 +635,7 @@ module Completions =
                         Detail = detail
                         TextEdit = Some(First { Range = newRange; NewText = newText })
                         FilterText = Some filterText
+                        Kind = Some CompletionItemKind.Reference
                 }
             | _, _ -> None
         | PE(PartialElement.InlineLink(Some text, Some _path, Some _anchor, range)) ->
@@ -637,6 +649,7 @@ module Completions =
                     Detail = detail
                     TextEdit = Some(First { Range = range; NewText = newText })
                     FilterText = Some filterText
+                    Kind = Some CompletionItemKind.Reference
             }
         | _ -> None
 
@@ -663,6 +676,7 @@ module Completions =
                 CompletionItem.Create(label) with
                     Detail = Some detail
                     TextEdit = Some(First { Range = range; NewText = label })
+                    Kind = Some CompletionItemKind.Reference
             }
 
 module Candidates =