io/fs: minor corrections to Glob doc

The documentation for Glob was copied from filepath.Glob, and needs a bit
of tweaking: paths are not rooted at slash; the separator is always '/'.

Fixes #43537

Change-Id: Id64daa137e2762b66a82a5b9e60bbe603f4e2f5c
Reviewed-on: https://go-review.googlesource.com/c/go/+/282173
Trust: Ian Lance Taylor <[email protected]>
Reviewed-by: Russ Cox <[email protected]>

Author: ianlancetaylor

src/io/fs/glob.go

@@ -22,7 +22,7 @@ type GlobFS interface {
 // Glob returns the names of all files matching pattern or nil
 // if there is no matching file. The syntax of patterns is the same
 // as in path.Match. The pattern may describe hierarchical names such as
-// /usr/*/bin/ed (assuming the Separator is '/').
+// usr/*/bin/ed.
 //
 // Glob ignores file system errors such as I/O errors reading directories.
 // The only possible returned error is path.ErrBadPattern, reporting that