* guix/scripts/lint.scm (guix): Remove duplicated lines for using
'srfi-34' and 'srfi-35' modules. These lines were introduced twice by
commits b210b35 and 002c57c.
* guix/scripts/import.scm (show-help): Add newline before a list of
importers.
* guix/scripts/lint.scm (show-help): Split a long description line.
* guix/scripts/package.scm (show-help): Improve docstrings for --install
and --remove options.
* guix/scripts/system.scm (show-help): Format actions the same way as
guix commands and importers are formatted.
* guix/scripts/lint.scm (call-with-accumulated-warnings): New procedure.
(with-accumulated-warnings): New macro.
(check-source): Add 'try-uris' and use it. Emit warnings only upon
failure.
* guix/scripts/lint.scm (%options) <--checkers>: Remove 'arg-handler'
parameter, and return a single value.
(guix-lint)[parse-options]: Remove 'arg-handler' parameter from
handlers. Remove second seed to 'args-fold*'.
* tests/guix-lint.sh: Add test.
Before that it would check all the URIs of each package.
* guix/scripts/lint.scm (validate-uri): Really return #f on failure and
#t otherwise.
(check-source): Replace 'for-each' with 'any'.
* guix/scripts/lint.scm (run-checkers): Check
whether (current-error-port) is a tty, and print the package being
checked and the checker currently running when it is.
* guix/scripts/lint.scm (starts-with-abbreviation?): New procedure.
(check-synopsis-style)[check-start-with-package-name]: Use it.
* tests/lint.scm ("synopsis: start with abbreviation"): New test.
* guix/scripts/lint.scm (package-name-regexp): New procedure.
(check-synopsis-style)[check-start-with-package-name]: Use it instead
of 'string-prefix-ci?'.
* tests/lint.scm ("synopsis: start with package name prefix"): New test.
* guix/scripts/lint.scm (check-description-style): Exception for
upper-case rule if the description starts with the package name.
* tests/lint.scm: Test it.
* guix/scripts/lint.scm (start-with-capital-letter?): Rename too...
(properly-starts-sentence?): Rewrite with regex and add digits.
(check-description-style, check-synopsis-style): Use it.
* tests/lint.scm: Add tests.
* guix/scripts/lint.scm (start-with-capital-letter?): Handle empty
strings.
(check-description-style): New check for end-of-sentence space.
* tests/lint.scm: Test it.
* guix/scripts/lint.scm (check-start-article): use "string-ci=?" instead of
"string=?".
* tests/lint.scm ("synopsis: starts with 'a'",
"synopsis: starts with 'an'"): New tests.
* guix/scripts/lint.scm (check-description-style,
check-synopsis-start-upper-case): New methods.
* tests/lint.scm ("description: does not start with an upper-case letter",
"synopsis: does not start with an upper-case letter"): New tests.
This allows editors to parse warnings correctly.
* guix/scripts/lint.scm (emit-warning): Use 'format' instead of
'warning', to avoid the "guix lint: " prefix in messages.
* tests/lint.scm (call-with-warnings): Indent.