feat: go to next and previous problem

[abose]

• Brackets had got to first problem option only. That is not very useful.
• This matches vscode implementation to go to next and prev problem from cursor.
• Goto first problem command is there for backward compatibility, but it has been omitted from UI.
• shortcut is ctrl-i and ctrl-shift-i in all platforms. we didnt use vscodes f8 key as f8 will be reserved for browser dev tools operations as phcode is web first editor and we will try to use browser shortcuts when possible.
• Vscode shortcut pack will use f8 and shift f8

[sonarqubecloud]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud