fix: ensure skip dimensions are valid

internal/core/file.go

@@ -225,6 +225,9 @@ func (f *File) FindLoc(ctx, s string, pad, count int, a Alert) (int, []int) {
 func (f *File) assignLoc(ctx string, blk nlp.Block, pad int, a Alert) (int, []int) {
 	loc := a.Span
 	for idx, l := range strings.SplitAfter(ctx, "\n") {
+		if loc[0] < 0 || loc[1] < 0 {
+			continue
+		}
 		// NOTE: This fixes #473, but the real issue is that `blk.Line` is
 		// wrong. This seems related to `location.go#41`, but I'm not sure.
 		//

testdata/fixtures/checks/Sequence/.vale.ini

@@ -6,3 +6,4 @@ LanguageTool.OF_ALL_TIMES = YES
 LanguageTool.APOS_ARE = YES
 LanguageTool.Metadata = YES
 LanguageTool.ARE_USING = YES
+LanguageTool.AMBIG = YES

testdata/styles/LanguageTool/AMBIG.yml

@@ -0,0 +1,10 @@
+---
+extends: sequence
+message: "Avoid ambiguous pronouns"
+level: warning
+ignorecase: true
+tokens:
+  - tag: NN|NNP|NNPS|NNS
+    skip: 7
+  - tag: PRP|PRP$
+    pattern: he|she|its?|they|his|her|their