[DOC] More docs for InstructionSequence.compile

[eightbitraptor]

This commit documents that you can also pass a File object to RubyVM::InstructionSequence.compile, instead of a string, and this will behave in a similar way to
RubyVM::InstructionSequence.compile_file

e.g.

❯ ./ruby -e "puts RubyVM::InstructionSequence.compile(File.open('test.rb')).disasm"
== disasm: #<ISeq:<compiled>@<compiled>:1 (1,0)-(2,21)>
local table (size: 1, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, kw: -1@-1, kwrest: -1])
[ 1] name@0
0000 putstring                              "Ruby"                    (   1)[Li]
0002 setlocal_WC_0                          name@0
0004 putself                                                          (   2)[Li]
0005 putobject                              "Hello, "
0007 getlocal_WC_0                          name@0
0009 dup
0010 objtostring                            <calldata!mid:to_s, argc:0, FCALL|ARGS_SIMPLE>
0012 anytostring
0013 concatstrings                          2
0015 opt_send_without_block                 <calldata!mid:puts, argc:1, FCALL|ARGS_SIMPLE>
0017 leave

~/git/ruby master* ≡ ⇡
❯ ./ruby -e "puts RubyVM::InstructionSequence.compile(File.open('test.rb').read).disasm"
== disasm: #<ISeq:<compiled>@<compiled>:1 (1,0)-(2,21)>
local table (size: 1, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, kw: -1@-1, kwrest: -1])
[ 1] name@0
0000 putstring                              "Ruby"                    (   1)[Li]
0002 setlocal_WC_0                          name@0
0004 putself                                                          (   2)[Li]
0005 putobject                              "Hello, "
0007 getlocal_WC_0                          name@0
0009 dup
0010 objtostring                            <calldata!mid:to_s, argc:0, FCALL|ARGS_SIMPLE>
0012 anytostring
0013 concatstrings                          2
0015 opt_send_without_block                 <calldata!mid:puts, argc:1, FCALL|ARGS_SIMPLE>
0017 leave

This is explicitly allowed by this code path in
rb_iseq_compile_with_option so we should document it.

    if (RB_TYPE_P(src, T_FILE)) {
        parse = rb_parser_compile_file_path;
    }
    else {
        parse = rb_parser_compile_string_path;
        StringValue(src);
    }