internal/lsp: use strings.EqualFold instead of ==

Change-Id: I34dc519f25fa976a959a749d4e1a525f5480b963
Reviewed-on: https://go-review.googlesource.com/c/tools/+/172664
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/internal/span/uri.go b/internal/span/uri.go
index 63d7ba8..c1c068b 100644
--- a/internal/span/uri.go
+++ b/internal/span/uri.go
@@ -62,7 +62,7 @@
 	// If we have the same URI basename, we may still have the same file URIs.
 	if fa, err := a.Filename(); err == nil {
 		if fb, err := b.Filename(); err == nil {
-			if filepath.Base(fa) == filepath.Base(fb) {
+			if strings.EqualFold(filepath.Base(fa), filepath.Base(fb)) {
 				// Stat the files to check if they are equal.
 				if infoa, err := os.Stat(fa); err == nil {
 					if infob, err := os.Stat(fb); err == nil {