[binggao1230]

WriteTo/Encode write values verbatim, but the parser trims surrounding whitespace, strips one matching quote pair, and treats a trailing \ or a """/''' prefix as a multi-line marker. So parse(encode(x)) != x for a whole class of ordinary values, and a trailing backslash aborts the entire load.

c := ini.New()
c.SetSection("s", map[string]string{"pw": "  s3cr3t ", "path": `C:\dir\`})
var b bytes.Buffer
c.WriteTo(&b)
c2 := ini.New(); c2.LoadStrings(b.String())
c2.Get("s.pw")   // "s3cr3t"  — surrounding spaces lost
c2.Get("s.path") // ""        — LoadStrings errors on the trailing `\`

The encoder now wraps only the values the parser would otherwise mangle (leading/trailing whitespace, matching surrounding quotes, trailing backslash, triple-quote prefix) in a quote style the existing parser strips back off, so no parser change is needed. Values that already round-trip are emitted byte-for-byte unchanged. Applied at every encoder site: lite and full section k-v and array items, plus default-section k-v and arrays.

Values containing a real newline still need a symmetric escape to round-trip (the parser only turns \n back into a newline when ReplaceNl is set), so those are left as-is.

Added round-trip tests for the affected value classes and a check that normal values are emitted unchanged. go test ./... passes.