Update the heuristics and examples for Mojo language to include the "comptime" keyword

[dgurchenkov]

I am updating a definition of an existing language.

Description

This PR contains updated heuristics and new examples for Mojo language. The language was added to Linguist more than a year ago and since then the language syntax has changed. In particular, we added a new keyword ("comptime") that is unique to the language and thus it makes sense to include it in the detection heuristics. I also added new examples that better reflect the current syntax of the language.

Checklist:

• I am fixing a misclassified language
  • I have included a new sample for the misclassified language:
    • Sample source(s):
      • https://github.com/modular/modular/blob/main/max/kernels/src/linalg/matmul/cpu/impl.mojo (as samples/Mojo/Matmul_25_7.mojo)
      • https://github.com/modular/modular/blob/main/mojo/stdlib/stdlib/collections/list.mojo (as samples/Mojo/List_25_7.mojo)
    • Sample license(s):
      • Apache License v2.0 with LLVM Exceptions: https://llvm.org/LICENSE.txt
      • License included in both sample files
  • I have updated the heuristics to distinguish my language from others using the same extension.

[lildude]

We do not change samples. These samples are used to train the classifier and whilst languages evolve, the content on GitHub may not, and as such we prefer to keep samples as they were when added and prefer to add more samples.

Please revert the changes to the samples and instead add more real-world samples representing the evolution of the language. Be sure to update the PR template to link to the original source of the new samples and state their license.

[dgurchenkov]

We do not change samples. These samples are used to train the classifier and whilst languages evolve, the content on GitHub may not, and as such we prefer to keep samples as they were when added and prefer to add more samples.

Please revert the changes to the samples and instead add more real-world samples representing the evolution of the language. Be sure to update the PR template to link to the original source of the new samples and state their license.

Thank you Colin for looking at this so quickly!
I reverted changes to the samples, and instead added two more sample files. Links to the sample files are in the updated description. License is stated and included in the files as well.

Please let me know if the changes are in line with your expectations, happy to change it further.

Also, if you don't mind me asking -- I have updated the language grammar in the repo linked from the linguist/blob/main/vendor/README.md file (https://github.com/modular/mojo-syntax) so I don't need to do anything in this PR, the grammar change will be pulled from the linked repo automatically on the next release. Is that right?