Move get_string

src/lib/builtins/variables.rs

src/lib/parser/assignments/checker.rs

src/lib/parser/loops.rs

src/lib/parser/mod.rs

src/lib/parser/shell_expand/mod.rs

src/lib/parser/shell_expand/words/methods/arrays.rs

src/lib/parser/shell_expand/words/methods/mod.rs

src/lib/parser/shell_expand/words/methods/strings.rs

src/lib/parser/shell_expand/words/mod.rs

src/lib/shell/flow.rs

src/lib/shell/job.rs

src/lib/shell/mod.rs

src/lib/shell/shell_expand.rs

src/lib/shell/variables/mod.rs