log errors that read-language produces when DrRacket calls it

collects/drracket/private/module-language-tools.rkt

@@ -155,7 +155,12 @@
                ;; info-result : (or/c #f   [#lang without a known language]
                ;;                     (vector <get-info-proc>) [no #lang line, so we use the '#lang racket' info proc]
                ;;                     <get-info-proc>  [the get-info proc for the program in the definitions]
-               [info-result (with-handlers ((exn:fail? (λ (x) #f)))
+               [info-result (with-handlers ((exn:fail? 
+                                             (λ (x)
+                                               (log-debug (format "DrRacket: error duing call to read-language for ~a:\n  ~a"
+                                                                  (or (send this get-filename) "<<unsaved file>>")
+                                                                  (regexp-replace* #rx"\n(.)" (exn-message x) "\n\\1  ")))
+                                               #f)))
                               (read-language 
                                port
                                (lambda () 

collects/scribblings/tools/tools.scrbl

@@ -273,6 +273,9 @@ as the @racket[_key] argument to the @racket[_get-info] function to do so:
           @item{@language-info-ref[drracket:opt-out-toolbar-buttons]}
           @item{@language-info-ref[color-lexer]}]
 
+If the call to @racket[read-language] raises an error, DrRacket logs the
+error via @racket[log-debug].
+
 @language-info-def[color-lexer]{
   When a language's @racket[_get-info] procedure responds to @racket['color-lexer], it
   is expected to return a procedure suitable to pass as the @racket[_get-token]