encoding.html: optimize escape performance

[ttytm]

Using constants instead of re-allocating the array results in an performance improvement of about 30%.

Tested with 100k iterations:
current: 84.042ms
consts: 58.604ms

Additionally, it replaces '"' with '"' and ''' with '''.
The values are the common replacements for " and ', e.g. also used for escaping in Go.

🤖 Generated by Copilot at 435ad5b

Refactor escape function in encoding/html module to use constant arrays.

🤖 Generated by Copilot at 435ad5b

• Define constant arrays html_escape_table and html_escape_table_len to store the HTML replacement characters for the escape function (link)
• Replace the literal arrays with the constant arrays in the escape function, making it more consistent and concise (link)

[spytheman]

Good work.