feat(picker): allow appending original window cword to prompt (#2878)

* feat(picker): allow appending original window cword to prompt

* add default mapping and document

* [docgen] Update doc/telescope.txt
skip-checks: true

* add mapping to README

also format README

* oops

* [docgen] Update doc/telescope.txt
skip-checks: true

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Co-authored-by: Github Actions <actions@github>

lua/telescope/mappings.lua

@@ -164,6 +164,7 @@ mappings.default_mappings = config.values.default_mappings
       ["<C-/>"] = actions.which_key,
       ["<C-_>"] = actions.which_key, -- keys from pressing <C-/>
       ["<C-w>"] = { "<c-s-w>", type = "command" },
+      ["<C-r><C-w>"] = actions.insert_original_cword,
 
       -- disable c-j because we dont want to allow new lines #2123
       ["<C-j>"] = actions.nop,