Update forwarded cmd.exe commands docs

Replaces nushell#1605 (which documented behavior across versions).

The "if no executable by that name exists" has been wrong since 0.94.0 (not disclosed in release notes, but consequence of 6c649809d38a687cd63b59ab028b7f30207e5663).

The "used to" (prior version 0.67 2022-08-16) is very old, and no longer worth it to keep.

Add information about forwarded commands overshadowing external files.

Author: Kissaki

book/coming_from_cmd.md

@@ -61,15 +61,12 @@ This table was last updated for Nu 0.67.0.
 
 ## Forwarded CMD.EXE commands
 
-Nu accepts and runs *some* of CMD.EXE's internal commands through `cmd.exe`.
+Nu accepts and runs *some* CMD.EXE commands through `cmd.exe`.
 
-The internal commands are: `ASSOC`, `CLS`, `ECHO`, `FTYPE`, `MKLINK`, `PAUSE`, `START`, `VER`, `VOL`
+The forwarded commands are: `ASSOC`, `CLS`, `ECHO`, `FTYPE`, `MKLINK`, `PAUSE`, `START`, `VER`, `VOL`
 
-These internal commands take precedence over external commands.
+These forwarded commands take precedence over external commands.
 
-For example, with a `ver.bat` file in the current working directory, executing `^ver` executes CMD.EXE's internal `VER` command, *NOT* the `ver.bat` file.
+For example, with a `ver.bat` file in the current working directory, executing `^ver` leads to the CMD.EXE `VER` being executed, *NOT* the `ver.bat` file.
 
 Executing `./ver` or `ver.bat` *will* execute the local bat file though.
-
-Note that Nushell has its own [`start` command](/commands/docs/start.md) which takes precedence.
-You can call the CMD.EXE's internal `START` command with the external command syntax `^start`.