[Fix] display-name: fix false positive when using memo

[golopot]

Fix #3303.

PR #3276 caused the following to be considered a component, while in v7.29.0 it is not considered a component:

const MemoizedMyComponent = React.memo(
  MyComponent,
  () => 1
)

This PR adds a check that the function being wrapped must return JSX to be considered a component.

The bug is so subtle and I am not sure this is the right way to fix it.

[codecov]

Codecov Report

Merging #3304 (b9aa04b) into master (e7fc22f) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #3304      +/-   ##
==========================================
+ Coverage   97.69%   97.70%   +0.01%     
==========================================
  Files         123      123              
  Lines        8746     8746              
  Branches     3168     3168              
==========================================
+ Hits         8544     8545       +1     
+ Misses        202      201       -1     

Impacted Files	Coverage Δ
lib/util/Components.js	98.91% <100.00%> (ø)
lib/util/jsx.js	95.60% <0.00%> (+1.09%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e7fc22f...b9aa04b. Read the comment docs.

[ljharb]

Thanks!