docs: drop --repo gh-cli from dnf install lines

The documented dnf install lines pin resolution to the gh-cli repo
with --repo gh-cli. That repo only ships the gh package, so on a
fresh Fedora install without git already present the install fails
with "nothing provides git needed by gh-2.87.3-1.x86_64 from gh-cli"
(cli#12808). Dropping --repo lets dnf pull git from the system repos
while still installing gh from gh-cli.

The maintainer suggested this in the issue thread after spotting
that other projects (docker, vagrant) use addrepo without the
restrictive --repo flag.

Closes cli#12808

Signed-off-by: Charlie Tonneslan <cst0520@gmail.com>

Author: Charlie Tonneslan

docs/install_linux.md

@@ -100,7 +100,7 @@ To install:
 ```bash
 sudo dnf install dnf5-plugins
 sudo dnf config-manager addrepo --from-repofile=https://cli.github.com/packages/rpm/gh-cli.repo
-sudo dnf install gh --repo gh-cli
+sudo dnf install gh
 ```
 
 To upgrade:
@@ -119,7 +119,7 @@ To install:
 ```bash
 sudo dnf install 'dnf-command(config-manager)'
 sudo dnf config-manager --add-repo https://cli.github.com/packages/rpm/gh-cli.repo
-sudo dnf install gh --repo gh-cli
+sudo dnf install gh
 ```
 
 To upgrade: