Add fatal? flag to error types; non-fatal errors are hidden by default in error list, not shown in summary

basis/compiler/errors/errors.factor

@@ -44,6 +44,7 @@ T{ error-type
    { icon "vocab:ui/tools/error-list/icons/linkage-error.tiff" }
    { quot [ +linkage-error+ errors-of-type values ] }
    { forget-quot [ compiler-errors get delete-at ] }
+   { fatal? f }
 } define-error-type
 
 : <compiler-error> ( error word -- compiler-error )

basis/ui/tools/error-list/error-list.factor

@@ -26,7 +26,7 @@ MEMO: error-icon ( type -- image-name )
 
 : <error-toggle> ( -- model gadget )
     #! Linkage errors are not shown by default.
-    error-types get keys [ dup +linkage-error+ eq? not <model> ] { } map>assoc
+    error-types get [ fatal?>> <model> ] assoc-map
     [ [ [ error-icon ] dip ] assoc-map <checkboxes> ]
     [ <mapping> ] bi ;
 

basis/ui/tools/listener/listener.factor

@@ -358,9 +358,8 @@ interactor "completion" f {
 } define-command-map
 
 : ui-error-summary ( -- )
-    all-errors [
-        [ error-type ] map prune
-        [ error-icon-path 1array \ $image prefix " " 2array ] { } map-as
+    error-counts keys [
+        [ icon>> 1array \ $image prefix " " 2array ] { } map-as
         { "Press " { $command tool "common" show-error-list } " to view errors." }
         append print-element nl
     ] unless-empty ;

core/source-files/errors/errors.factor

@@ -12,7 +12,7 @@ TUPLE: source-file-error error asset file line# ;
 : group-by-source-file ( errors -- assoc )
     H{ } clone [ [ push-at ] curry [ dup file>> ] prepose each ] keep ;
 
-TUPLE: error-type type word plural icon quot forget-quot ;
+TUPLE: error-type type word plural icon quot forget-quot { fatal? initial: t } ;
 
 GENERIC: error-type ( error -- type )
 
@@ -34,12 +34,12 @@ error-types [ V{ } clone ] initialize
     error-types get at icon>> ;
 
 : error-counts ( -- alist )
-    error-types get [ nip dup quot>> call( -- seq ) length ] assoc-map ;
+    error-types get
+    [ nip dup quot>> call( -- seq ) length ] assoc-map
+    [ [ fatal?>> ] [ 0 > ] bi* and ] assoc-filter ;
 
 : error-summary ( -- )
-    error-counts
-    [ nip 0 > ] assoc-filter
-    [
+    error-counts [
         over
         [ word>> write ]
         [ " - show " write number>string write bl ]