fix(man): filter OSC 8 hyperlink markup #29171

Problem: `man cmake` shows "8;;https://cmake.orghttps://cmake.org8;;"
Solution: Remove noise so that it shows as "https://cmake.org".
See also: https://en.wikipedia.org/wiki/ANSI_escape_code#OSC

runtime/lua/man.lua

@@ -35,7 +35,7 @@ local function highlight_line(line, linenr)
   ---@type string[]
   local chars = {}
   local prev_char = ''
-  local overstrike, escape = false, false
+  local overstrike, escape, osc8 = false, false, false
 
   ---@type table<integer,{attr:integer,start:integer,final:integer}>
   local hls = {} -- Store highlight groups as { attr, start, final }
@@ -139,6 +139,12 @@ local function highlight_line(line, linenr)
       prev_char = ''
       byte = byte + #char
       chars[#chars + 1] = char
+    elseif osc8 then
+      -- eat characters until String Terminator or bell
+      if (prev_char == '\027' and char == '\\') or char == '\a' then
+        osc8 = false
+      end
+      prev_char = char
     elseif escape then
       -- Use prev_char to store the escape sequence
       prev_char = prev_char .. char
@@ -157,8 +163,11 @@ local function highlight_line(line, linenr)
           add_attr_hl(match + 0) -- coerce to number
         end
         escape = false
-      elseif not prev_char:match('^%[[\032-\063]*$') then
+      elseif prev_char == ']8;' then
-        -- Stop looking if this isn't a partial CSI sequence
+        osc8 = true
+        escape = false
+      elseif not prev_char:match('^[][][\032-\063]*$') then
+        -- Stop looking if this isn't a partial CSI or OSC sequence
         escape = false
       end
     elseif char == '\027' then

test/functional/plugin/man_spec.lua

@@ -117,6 +117,29 @@ describe(':Man', function()
       ]])
     end)
 
+    it('clears OSC 8 hyperlink markup from text', function()
+      feed(
+        [[
+        ithis <C-v><ESC>]8;;http://example.com<C-v><ESC>\Link Title<C-v><ESC>]8;;<C-v><ESC>\<ESC>]]
+      )
+
+      screen:expect {
+        grid = [=[
+        this {c:^[}]8;;http://example.com{c:^[}\Link Title{c:^[}]8;;{c:^[}^\ |
+        {eob:~                                                   }|*3
+                                                            |
+      ]=],
+      }
+
+      exec_lua [[require'man'.init_pager()]]
+
+      screen:expect([[
+      ^this Link Title                                     |
+      {eob:~                                                   }|*3
+                                                          |
+      ]])
+    end)
+
     it('highlights multibyte text', function()
       feed(
         [[