Floating-Points Without Leading Digit In CSV Are Inferred As Strings

[brianrackle]

Describe the bug
infer_field_schema in csv/reader.rs will infer a string from a floating-point without a leading digit (e.g. ".2"). Numbers between 1 and 0 that don't have leading zeros and are still valid and the zero is inferred. For example, ".2" and "0.2" should be considered equivalent.

To Reproduce
Steps to reproduce the behavior:
Use infer_field_schema on any float between 1 and 0 without a leading digit, such as:
.1
.2
.3
.4
etc...

Expected behavior
A digit should not be required to proceed the decimal for a float to be inferred so that ".2" and "0.2" are equivalent and both inferred as floats.

Additional context
I only tested CSV parsing, so this bug might be present with other file formats.