use ? line numbers when position is unknown in --lint

I only did this for compile errors, not parse errors or lint errors.

src/fennel-ls.fnl

@@ -2,17 +2,17 @@
 (local dispatch (require :fennel-ls.dispatch))
 (local json-rpc (require :fennel-ls.json-rpc))
 (local files (require :fennel-ls.files))
-(local {: severity->string} (require :fennel-ls.message))
+(local {: severity->string &as message} (require :fennel-ls.message))
 
-(fn print-diagnostic [filename message ?range ?severity]
+(fn print-diagnostic [filename msg range ?severity]
   (print (: "%s:%s:%s: %s: %s" :format
             filename
             ;; LSP line numbers are zero-indexed, but Emacs and Vim both use
             ;; 1-indexing for this.
-            (+ (or (?. ?range :start :line) 0) 1)
-            (or (?. ?range :start :character) "?")
+            (if (= range message.unknown-range) "?" (+ range.start.line 1))
+            (if (= range message.unknown-range) "?" range.start.character)
             (or (. severity->string ?severity) "?")
-            message)))
+            msg)))
 
 (fn initialize [server]
   (let [params {:id 1

src/fennel-ls/compiler.fnl

@@ -300,7 +300,7 @@ identifiers are declared / referenced in which places."
 
     (λ on-compile-error [_ msg ast call-me-to-reset-the-compiler]
       (let [range (or (message.ast->range server file ast)
-                      (line+byte->range server file 1 1))]
+                      message.unknown-range)]
         (table.insert diagnostics
           {:range range
            :message msg

src/fennel-ls/message.fnl

@@ -66,6 +66,9 @@ LSP json objects."
    : id
    :result (nullify ?result)})
 
+(local unknown-range {:start {:line 0 :character 0}
+                      :end {:line 0 :character 0}})
+
 (λ ast->range [server file ?ast]
   (case (fennel.ast-source ?ast)
     {: bytestart : byteend} {:start (utils.byte->position file.text bytestart
@@ -133,4 +136,5 @@ LSP json objects."
  : diagnostics
  : severity
  : severity->string
- : show-message}
+ : show-message
+ : unknown-range}