fix parsing of <digit>.<op> to always favor the dot version of the op…

…erator over floating-point literals. closes JuliaLang#4604

we were missing the .+ .- and .' cases

src/julia-parser.scm

@@ -125,7 +125,7 @@
 ;; characters that can be in an operator
 (define (opchar? c) (string.find op-chars c))
 ;; characters that can follow . in an operator
-(define (dot-opchar? c) (and (char? c) (string.find ".*^/\\" c)))
+(define (dot-opchar? c) (and (char? c) (string.find ".*^/\\+-'" c)))
 (define (operator? c) (memq c operators))
 
 (define (skip-to-eol port)