Enhance open.mp support: autocomplete, hover docs, syntax highlighting, snippets, and compiler integration

[stefanutc1]

This PR introduces several quality-of-life and IntelliSense improvements for open.mp and modern Pawn development:

Summary of Changes

1. Autocomplete & Hover Documentation:

   • Added a built-in data dictionary containing comprehensive documentation, signatures, parameter descriptions, and return values for open.mp and standard SA-MP natives, callbacks, and constants.
   • Enhanced doHover and doSignHelp to show rich Markdown tooltips and active parameter hints.
   • Improved symbol parsing to handle Pawn tags (Float:, bool:, PlayerText:, etc.) and command definitions (CMD:, YCMD:) without losing definition references.
   • Allowed multi-word macro expressions in #define parsing.

2. Syntax Highlighting & Tokenization:

   • Refined preprocessor rules in Pawn.tmLanguage to properly recognize #elif, diagnostic directives (#error, #warning), and extended #pragma flags (warning, option, compatibility, disablestate, naked, reparse).
   • Added highlighting for modern storage types, modifiers, and built-in open.mp tags (bool, Float, File, Text, Text3D, PlayerText, PlayerText3D, Menu, DB, DBResult, Bit, Iterator, Task, Timer, Group, BitArray, ConstString, struct, decl).
   • Added highlighting for command macros (CMD:, COMMAND:, YCMD:, flags:), operators (sizeof, tagof, defined), control keywords (foreach, yield), and language constants.

3. Code Snippets:

   • Added a dedicated snippets/pawn.json catalog registered in package.json with snippets for:
     • Common callbacks (OnPlayerConnect, OnPlayerDisconnect, OnPlayerSpawn, OnPlayerDeath, OnDialogResponse, OnPlayerWeaponShot, etc.).
     • Fast command skeletons (CMD:, YCMD:, admin commands with permission checks).
     • Performance-optimized pool loops using GetPlayerPoolSize(), GetVehiclePoolSize(), and GetActorPoolSize(), as well as foreach iterators.
     • Include guards and ALS hook patterns.

4. Compiler Integration & Problem Matcher:

   • Fixed invalid trailing commas in the generated tasks.json template in src/client/task.ts.
   • Updated the $pawncc problem matcher in package.json with a more flexible regular expression that accurately parses standard compiler output, column numbers, warning/error codes, and line ranges.
   • Configured fileLocation to "autoDetect" so compiler diagnostics map to the exact file and line directly in the VS Code Problems panel.