cmd/cue: help mod edit: fix copy/paste error

This updates the help text emitted by "cue help mod edit" and replaces
some prose left in place from copying Go's equivalent help text.

Fixes #3401.

Signed-off-by: Jonathan Matthews <[email protected]>
Change-Id: I0d1b2859e00aacf69de30ad828706736bf763c5e
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1201449
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Daniel Martí <[email protected]>

Author: jpluscplusm

cmd/cue/cmd/modedit.go

@@ -43,8 +43,8 @@ The -require=path@version and -drop-require=path@majorversion flags add
 and drop a requirement on the given module path and version. Note that
 -require overrides any existing requirements on path. These flags are
 mainly for tools that understand the module graph. Users should prefer
-'cue get path@version' which makes other go.mod adjustments as needed
-to satisfy constraints imposed by other modules.
+'cue mod get path@version' which makes other cue.mod adjustments as
+needed to satisfy constraints imposed by other modules.
 
 The --module flag changes the module's path (the module.cue file's module field).
 The --source flag changes the module's declared source.