[Documentation] Missing data type (#817)

* [Documentation] Missing data type

In the documentation of Floating Point is this example:

```
n = 0.005;  // 0.005 is a floating point constant
```
This code simply won't compile and get this error :   
'n' does not name a type

so this Line should be : 

```
const float n = 0.005;  // 0.005 is a floating point constant
```
Although this error may seem trivial for some professional , but I think it seems misleading to newcomers.

* Update Language/Variables/Constants/floatingPointConstants.adoc

Co-authored-by: per1234 <[email protected]>

Co-authored-by: per1234 <[email protected]>

Language/Variables/Constants/floatingPointConstants.adoc

@@ -34,7 +34,7 @@ Similar to integer constants, floating point constants are used to make code mor
 
 [source,arduino]
 ----
-n = 0.005;  // 0.005 is a floating point constant
+float n = 0.005;  // 0.005 is a floating point constant
 ----
 [%hardbreaks]