Fix French keyboard comment/uncomment shortcut for all platforms

[khuntvidisha13]

Problem

On French (AZERTY) keyboard on macOS, the comment/uncomment shortcut
was conflicting with the font size increase shortcut (⌘+).

Fix

Updated PDE_fr.properties to use platform-specific keybindings:

• macOS: meta pressed COLON
• Windows: ctrl pressed COLON
• Linux: ctrl pressed COLON

Related

Fixes #1381

[SableRaf]

Hi @khuntvidisha13, thanks for taking the time to look into this.

The issue linked in the PR does not seem related to these changes. Could you double-check and link the correct issue?

We also ask that contributors get assigned before opening a PR. You can find more details in our CONTRIBUTING.md file.

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A note on GSoC: We receive many contributions around this time of year from GSoC applicants. Just a heads-up that our application process does not require you to submit a PR. Please check out this thread on the forum for more details on how to apply.

[khuntvidisha13]

Hi @SableRaf, I recently started contributing to open source and was not fully aware of the assignment policy. I apologize for linking the wrong issue and for opening the PR without being assigned first. I will make sure to follow the CONTRIBUTING.md guidelines going forward. Thank you for the guidance.