all: add limit to accumulated errors / warnings (#11183)

cmd/tools/vcomplete.v

@@ -131,6 +131,7 @@ const (
 		'-w',
 		'-print-v-files',
 		'-error-limit',
+		'-warn-error-limit',
 		'-os',
 		'-printfn',
 		'-cflags',

cmd/v/help/build.txt

@@ -82,6 +82,10 @@ NB: the build flags are shared with the run command too:
          d) the function name
       NB: if you want to output the profile info to stdout, use `-profile -`.
 
+   -warn-error-limit <limit>
+      Limit of warnings / errors that will be accumulated (defaults to 100).
+      Settings this to a negative value will disable the limit.
+
    -profile-no-inline
       Skip [inline] functions when profiling.