Fix string redundancy in halt() and correct grammar/comments across P2

[apoorvsamota]

Summary
This PR resolves a C string literal redundancy, fixes grammatical errors in documentation and comments, and cleans up the P2 codebase.

Specific Fixes:

• String Redundancy (main.c): Removed the explicit \0 from the format string in halt() (cprintf("Bye COL%d!\n\0", 331);). The C compiler automatically null-terminates string literals, making the explicit escape sequence redundant and causing an unnecessary double-null in .rodata.
• Grammar (p2-print.md): Hyphenated "Self-study" to correct compound phrasing.
• Grammar (console.c): Fixed capitalization in the cprintf documentation comment (Only understands...).
• Comment Clarity (uart.c): Clarified the baud rate calculation comment to reflect the 115200/9600 divisor logic used in uartinit().

[pramod-batni]

Accepting.