Raise exception when collecting a noncommutative symbol

[JMSS-Unknown]

Fixes #14608
The exception is only raised when the expression contains the noncommutative symbol

As stated in #14608 (comment)

• simplify
  • Raise exception when collecting a noncommutative symbol

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• simplify
  • Raise exception when collecting a noncommutative symbol (#15447 by @JMSS-Unknown)

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Fixes #14608
The exception is only raised when the expression contains the noncommutative symbol

As stated in https://github.com/sympy/sympy/issues/14608#issuecomment-434138072

<!-- BEGIN RELEASE NOTES -->
* simplify
  * Raise exception when collecting a noncommutative symbol
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.