Wrong rendering output for \coloneq operator

[Flydroid]

Description

I noticed that the \coloneq operator gets rendered differently than its input := .
To showcase the issue it was necessary to show images of latex renders.

Steps to Reproduce

Enter: x:=5

Actual Behavior

Which results in latex $$ x\coloneq5 $$ and the redering is:

Expected Behavior

The input results in the same latex but the rendering should be:

in accordance to the mathtool package: https://ftpmirror1.infania.net/mirror/CTAN/macros/latex/contrib/mathtools/mathtools.pdf

Environment

Mathlive version: 0.103.0 on https://cortexjs.io/mathlive/demo/

Solution

I think I can provide a pull request with a fix, but would require some guides.
The \coloneq operator is defined here:

mathlive/src/latex-commands/definitions-utils.ts

Line 301 in c1ea306

coloneq: '{\\mathop{\\char"3A\\char"2212}}',

The mathtool packages now shows \coloneqq as a legacy.
It would propose to change the line 301 to the same as for \coloneqq:
coloneq: '{\\mathop{\\char"2254}}', // ≔
Not sure though if more of the mathtool package code should be updated.

[arnog]

Yep, you got the fix. Worth also looking at p. 31 of the mathtools package to double check other changes and make the definitions in MathLive are consistent.