JS: Update and fix docs, fix Number.toString() with decimals (#4168)

* Update and fix JS docs

This could really use some automation, atleast for API reference
There are TypeScript definitions and typedocs, we don't need to be monkeys copying and reformatting this to API reference by hand

* Fix bugged character

* JS: Fix Number.toString() with decimals

* Fix

* Forgot this one

* docs: mention per-view child format

* Added @portasynthinca3 to docs' codeowners

* Updated CODEOWNERS

---------

Co-authored-by: Anna Antonenko <portasynthinca3@gmail.com>
Co-authored-by: hedger <hedger@nanode.su>
Co-authored-by: hedger <hedger@users.noreply.github.com>

documentation/js/js_storage.md

@@ -52,7 +52,7 @@ File information structure.
 
 ## File
 
-This class implements methods for working with file. To get an object of the File class, use the `OpenFile` method.
+This class implements methods for working with file. To get an object of the File class, use the `openFile` method.
 
 <br>
 
@@ -186,6 +186,36 @@ Copies bytes from the R/W pointer in the current file to the R/W pointer in anot
 
 # Methods
 
+## openFile()
+
+Opens a file.
+
+**Parameters**
+
+- path: The path to the file
+- accessMode: How to access the file (`"r"`, `"w"` or `"rw"`)
+- openMode: How to open the file (`"open_existing"`, `"open_always"`, `"open_append"`, `"create_new"` or `"create_always"`)
+
+**Returns**
+
+A `File` object on success, `undefined` otherwise.
+
+<br>
+
+## fileExists()
+
+Detects whether a file exists.
+
+**Parameters**
+
+- path: The path to the file
+
+**Returns**
+
+`true` if file exists, `false` otherwise.
+
+<br>
+
 ## arePathsEqual()
 
 Determines whether the two paths are equivalent. Respects filesystem-defined path equivalence rules.