Enable ruff's flake8-implicit-str-concat (ISC) rules

[seisman]

Description of proposed changes

Enable ISC rules.

Address #2741.

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If wrapping a new module, open a 'Wrap new GMT module' issue and submit reasonably-sized PRs.
• If adding new functionality, add an example to docstrings or tutorials.
• Use underscores (not hyphens) in names of Python files and directories.

Slash Commands

You can write slash commands (/command) in the first line of a comment to perform
specific operations. Supported slash commands are:

• /format: automatically format and lint the code
• /test-gmt-dev: run full tests on the latest GMT development version

[yvonnefroehlich]

Sofar I did not follow the PRs related to issue #2741 in greater detail. So, maybe I am missing some context here, but I am wondering why the ISC rule is not added to the list in pyproject.toml in contrast to the other ruff rules:

pygmt/pyproject.toml

Lines 100 to 112 in 78dfcf1

	[tool.ruff.lint]
	select = [
	"B", # flake8-bugbear
	"E", # pycodestyle
	"F", # pyflakes
	"I", # isort
	"NPY", # numpy
	"PD", # pandas-vet
	"PL", # pylint
	"SIM", # flake8-simplify
	"UP", # pyupgrade
	"W", # pycodestyle warnings
	]

[seisman]

Sofar I did not follow the PRs related to issue #2741 in greater detail. So, maybe I am missing some context here, but I am wondering why the ISC rule is not added to the list in pyproject.toml in contrast to the other ruff rules:

pygmt/pyproject.toml

Lines 100 to 112 in 78dfcf1

	[tool.ruff.lint]
	select = [
	"B", # flake8-bugbear
	"E", # pycodestyle
	"F", # pyflakes
	"I", # isort
	"NPY", # numpy
	"PD", # pandas-vet
	"PL", # pylint
	"SIM", # flake8-simplify
	"UP", # pyupgrade
	"W", # pycodestyle warnings
	]

Thanks for catching it. I forgot to add it. Now added in 0d78ee5