fix: deprecation warning: sprintf -> snprintf

[sp0lsh]

Changes:
Use snprintf instead of sprintf.

Results:
Works the same. Avoid deprecation warnings during building, i. e.

warning: 'sprintf' is deprecated: This function is provided for compatibility reasons only.  Due to security concerns inherent in the design of sprintf(3), it is highly recommended that you use snprintf(3) instead. [-Wdeprecated-declarations]
4193 |         sprintf(buffer, "#%03i#", iconId);
     |         ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.2.sdk/usr/include/_stdio.h:274:1: note: 'sprintf' has been explicitly marked deprecated here
 274 | __deprecated_msg("This function is provided for compatibility reasons only.  Due to security concerns inherent in the design of sprintf(3), it is highly recommended that you use snprintf(3) instead.")
     | ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.2.sdk/usr/include/sys/cdefs.h:218:48: note: expanded from macro '__deprecated_msg'
 218 |         #define __deprecated_msg(_msg) __attribute__((__deprecated__(_msg)))
     |                                                       ^
1 warning generated.

stdio.h references:

• https://linux.die.net/man/3/snprintf
• https://cplusplus.com/reference/cstdio/snprintf/
• https://cplusplus.com/reference/cstdio/sprintf/