Adds Go float and imaginary literal forms per Go spec § Floating-point
literals and § Imaginary literals:
3.14 .5 1. 1e10 1.5e-3 2.0e+2 1E5 (floats)
2i 3.14i 1e2i (imag)
gl-read-number! returns one of "int" / "float" / "imag"; gl-finish-number!
factors out the post-mantissa exponent + 'i' suffix logic so the int /
float / leading-dot-float paths all share it. scan! adds a .<digit>
branch ahead of the operator matcher so '.5' tokenises as float.
ASI trigger list extended to include float + imag (Go spec § Semicolons:
all literal types trigger).
Greedy-grammar pin (a single test '1.method' lexes as float ident),
since the Go spec says the '.' after a digit always belongs to the
number, never to a following identifier.
Hex floats (0x1.fp0) deferred — not commonly used.
lex 114/114.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>