feat(nvim_open_term): convert LF => CRLF (#26384)

Problem:
Unlike termopen(), nvim_open_term() PTYs do not carriage-return the
cursor on newline ("\n") input.

    nvim --clean
    :let chan_id = nvim_open_term(1, {})
    :call chansend(chan_id, ["here", "are", "some", "lines"])

Actual behavior:

    here
        are
           some
               lines

Expected behaviour:

    here
    are
    some
    lines

Solution:
Add `force_crlf` option, and enable it by default.

runtime/lua/vim/_meta/api.lua

@@ -1446,6 +1446,8 @@ function vim.api.nvim_notify(msg, log_level, opts) end
 ---                 is sent as a "\r", not as a "\n". `textlock` applies. It
 ---                 is possible to call `nvim_chan_send()` directly in the
 ---                 callback however. ["input", term, bufnr, data]
+---               • force_crlf: (boolean, default true) Convert "\n" to
+---                 "\r\n".
 --- @return integer
 function vim.api.nvim_open_term(buffer, opts) end
 

runtime/lua/vim/_meta/api_keysets.lua

@@ -217,6 +217,7 @@ error('Cannot require a meta file')
 
 --- @class vim.api.keyset.open_term
 --- @field on_input? function
+--- @field force_crlf? boolean
 
 --- @class vim.api.keyset.option
 --- @field scope? string