Flag using "solve for" instead of "solve"

## Description

In the past day or two I've noticed at least two people on YouTube saying things like "solve for the problem" instead of "solve the problem". The correct usage of "solve for" is with one of the variables in an equation.

## Resources

This may be too recent to have any discussions yet.

## Examples

I did some Googling to see if it's more widely used:
- [How can i **solve for** this **issue** with the logical flow](https://au.mathworks.com/matlabcentral/answers/823225-how-can-i-solve-for-this-issue-with-the-logical-flow)
- [Can you help me **solve for** the **problem** email message](https://answers.microsoft.com/en-us/msoffice/forum/all/can-you-help-me-solve-for-the-problem-email/61019945-e0c8-4323-a9f5-3378970006d3)
- ... explain when you **solve for** the wrong **problem** not only do you not get the solution ...
- [Can't figure out how to use **solve for** this **problem**](https://nl.mathworks.com/matlabcentral/answers/259108-can-t-figure-out-how-to-use-solve-for-this-problem)
- [this is a how to **solve for** this git **problem**: fatal: unable ...](https://gist.github.com/ftabashir/f06287693192b946799f9645bd2781f5)
- To **solve for** the **issue** in the meantime, I roll´ed back our package file to 1.0.15
- I've even added a const [noOfPages] to **solve for** this **issue**.
- however the good news is that this has already been **solved for** because the ad520 also has its own ways to play sound samples
- Now, if you don't get it in six attempts on the left hand side, you will see here the actual word that you couldn't **solve for**.
- Um, it can still weigh up to 10 tons. That's not easy to turn. Engineers **solve for** this by floating the glass on mercury.

No files, tests, or entry points are named in the issue. Locate the grammar-checking rule definitions and their tests, then verify that “solve for” is flagged when followed by a problem, issue, or similar object while valid use with an equation variable remains accepted.

Written by the indexing model from the issue text.