refactor: move non-symbols to defs.h headers

src/nvim/ex_cmds_defs.h

@@ -229,3 +229,28 @@ typedef struct {
     bool bar;
   } magic;
 } CmdParseInfo;
+
+/// flags for do_ecmd()
+enum {
+  ECMD_HIDE       = 0x01,  ///< don't free the current buffer
+  ECMD_SET_HELP   = 0x02,  ///< set b_help flag of (new) buffer before opening file
+  ECMD_OLDBUF     = 0x04,  ///< use existing buffer if it exists
+  ECMD_FORCEIT    = 0x08,  ///< ! used in Ex command
+  ECMD_ADDBUF     = 0x10,  ///< don't edit, just add to buffer list
+  ECMD_ALTBUF     = 0x20,  ///< like ECMD_ADDBUF and set the alternate file
+  ECMD_NOWINENTER = 0x40,  ///< do not trigger BufWinEnter
+};
+
+/// for lnum argument in do_ecmd()
+enum {
+  ECMD_LASTL = 0,   ///< use last position in loaded file
+  ECMD_LAST  = -1,  ///< use last position in all files
+  ECMD_ONE   = 1,   ///< use first line
+};
+
+/// Previous :substitute replacement string definition
+typedef struct {
+  char *sub;            ///< Previous replacement string.
+  Timestamp timestamp;  ///< Time when it was last set.
+  list_T *additional_elements;  ///< Additional data left from ShaDa file.
+} SubReplacementString;