docs: fix typos (#21196)

Co-authored-by: zeertzjq <zeertzjq@outlook.com>
Co-authored-by: Raphael <glephunter@gmail.com>
Co-authored-by: Gregory Anders <greg@gpanders.com>

src/nvim/api/vim.c

@@ -236,7 +236,7 @@ void nvim_set_hl_ns_fast(Integer ns_id, Error *err)
 ///
 /// @param keys         to be typed
 /// @param mode         behavior flags, see |feedkeys()|
-/// @param escape_ks    If true, escape K_SPECIAL bytes in `keys`
+/// @param escape_ks    If true, escape K_SPECIAL bytes in `keys`.
 ///                     This should be false if you already used
 ///                     |nvim_replace_termcodes()|, and true otherwise.
 /// @see feedkeys()

src/nvim/getchar.c

@@ -2342,7 +2342,9 @@ void check_end_reg_executing(bool advance)
 static int vgetorpeek(bool advance)
 {
   int c, c1;
-  bool timedout = false;  // waited for more than 1 second for mapping to complete
+  bool timedout = false;  // waited for more than 'timeoutlen'
+                          // for mapping to complete or
+                          // 'ttimeoutlen' for complete key code
   int mapdepth = 0;  // check for recursive mapping
   bool mode_deleted = false;  // set when mode has been deleted
   int new_wcol, new_wrow;

src/nvim/testdir/test_vimscript.vim

@@ -6642,7 +6642,7 @@ func Test_invalid_function_names()
   endtry
   call assert_equal(1, caught_e884)
 
-  " function name folowed by #
+  " function name followed by #
   let caught_e128 = 0
   try
     func! test2() "#