Keep CodeMirror cursor visible at zoom levels

[shriram-svg]

Description

Fixes #2223.

The CodeMirror cursor is rendered as a one-pixel border. At some application zoom levels that border can round down and disappear, especially when the cursor is positioned at the end of a line. This keeps the existing CodeMirror/theme cursor color behavior but raises the cursor border width to 2px in the app's global editor styles.

Issue fixed

• Disappearing edit-mode cursor at some zoom levels (Disappearing Cursor #2223).

Type of changes

• 🔘 Bugfix (Change that fixed an issue)
• ⚪ Breaking change (Change that can cause existing functionality to change)
• ⚪ Improvement (Change that improves the code. Maybe performance or development improvement)
• ⚪ Feature (Change that adds new functionality)
• ⚪ Documentation change (Change that modifies documentation. Maybe typo fixes)

Verification

• NODE_PATH=/Users/shriramvasudevan/worktrees/bounties/boostnote-2847/node_modules PATH=/Users/shriramvasudevan/worktrees/bounties/boostnote-2847/node_modules/.bin:$PATH stylus --use /Users/shriramvasudevan/worktrees/bounties/boostnote-2847/node_modules/nib --import browser/styles/index.styl --print browser/main/global.styl
• git diff --check

yarn compile could not be run from the shared installed dependency tree because grunt is not installed there.

Checklist:

• 🔘 My code follows the project code style
• ⚪ I have written test for my code and it has been tested
• ⚪ All existing tests have been passed
• ⚪ I have attached a screenshot/video to visualize my change if possible
• 🔘 This PR will modify the UI or affects the UX
• ⚪ This PR will add/update/delete a keybinding