fix(glob): handle numeric literals in pattern matching (#37257)

Problem:
vim.glob.to_lpeg() errors when patterns contain numeric literals
(like the '1' in '.ps*1') because LPeg interprets numeric strings
as indexed grammar rule references. For example:
  vim.glob.to_lpeg('.ps*1')
  E5108: Lua: rule '1' undefined in given grammar

Solution:
Prefix all rule names with '_' in the end_seg() function to prevent
literal numbers from being interpreted as LPeg indexed rules. This
ensures pattern components like '1', '2', etc. are treated as
regular rule names rather than special references.

test/functional/lua/glob_spec.lua

@@ -67,6 +67,9 @@ describe('glob', function()
       eq(true, match('a*b*[cy]*d*e*', 'axbxcxdxexxx'))
       eq(true, match('a*b*[cy]*d*e*', 'axbxyxdxexxx'))
       eq(true, match('a*b*[cy]*d*e*', 'axbxxxyxdxexxx'))
+      eq(true, match('.ps*1', '.ps1'))
+      eq(true, match('.ps*1', '.psaa1'))
+      eq(false, match('.ps*1', '.ps1a'))
     end)
 
     it('should match ? wildcards', function()