cmdutil: warnings not issued in remove if subrepopath overlaps

Previously a subrepository "sub" would cause no warnings to be issued
for a file "subnot/a" if it is not removed when calling:

hg remove -S "subnot/a"

mercurial/cmdutil.py

@@ -2481,14 +2481,15 b' def remove(ui, repo, m, prefix, after, f'
     for f in files:
         def insubrepo():
             for subpath in wctx.substate:
-                if f.startswith(subpath):
+                if f.startswith(subpath + '/'):
                     return True
             return False
 
         count += 1
         ui.progress(_('deleting'), count, total=total, unit=_('files'))
         isdir = f in deleteddirs or wctx.hasdir(f)
-        if f in repo.dirstate or isdir or f == '.' or insubrepo():
+        if (f in repo.dirstate or isdir or f == '.'
+            or insubrepo() or f in subs):
             continue
 
         if repo.wvfs.exists(f):

tests/test-subrepo.t

@@ -53,6 +53,15 b' test handling .hgsubstate "added" explic'
   7cf8cfea66e410e8e3336508dfeec07b3192de51
   .hgsub .hgsubstate
 
+Subrepopath which overlaps with filepath, does not change warnings in remove()
+
+  $ mkdir snot
+  $ touch snot/file
+  $ hg remove -S snot/file
+  not removing snot/file: file is untracked
+  [1]
+  $ rm -r snot
+
 Revert subrepo and test subrepo fileset keyword:
 
   $ echo b > s/a