file-wrong-format.txt

I had php file in repo that was being shown as Hack file.

so what I did was to add a .gitattributes file in my root dir and 

creating a .gitattributes file:

Is .gitattributes a file or a folder ? How do I create it ?
Windows : Create a new text file (Right click>new>text file) within windows explorer and rename it (Shortcut : F2) as follows

.gitattributes.
Note : That is DOT + gitattributes + DOT, windows will remove the trailing DOT for you producing the appropriate filename

Unix : and it's variants (Ubuntu, Raspberrian, Mac OS etc.)

touch .gitattributes
Alternatively : Clone the Git Attributes repository and move/copy the .gitattributes file that is applicable to your repository (Footnote 1 and 2).

Where should one add the file ? Under the repository root, X:\PATH\TO\Repository\, or the Git folder, X:\PATH\TO\Repository\.git\ ?
There are two locations where one can add the Git attributes file

    \Repository                        (1)
    \Repository\.git\info\attributes   (3)
Adding a .gitattributes file here sets the attributes "Universally".
Creating the .gitattributes file here sets the attributes "Personally", that is the repository upon one's own machine. While inadvisable you may a have good reason for doing so .

wrote a line in .gitattributes:

> *.php linguist-language=PHP

and commited the changes and pushed.
THe .php files were shown as PHP.

sources:

https://stackoverflow.com/questions/18331048/how-to-create-a-git-attributes-file
https://github.com/github/linguist#overrides