Fix typos in docs (JuliaLang#54059)

base/compiler/ssair/domtree.jl

@@ -202,7 +202,7 @@ DFS(blocks::Vector{BasicBlock}, is_post_dominator::Bool=false) = DFS!(DFSTree(0)
 """
 Keeps the per-BB state of the Semi NCA algorithm. In the original formulation,
 there are three separate length `n` arrays, `label`, `semi` and `ancestor`.
-Instead, for efficiency, we use one array in a array-of-structs style setup.
+Instead, for efficiency, we use one array in an array-of-structs style setup.
 """
 struct SNCAData
  semi::PreNumber

doc/src/manual/arrays.md

@@ -793,7 +793,7 @@ Indexing by a boolean vector `B` is effectively the same as indexing by the
 vector of integers that is returned by [`findall(B)`](@ref). Similarly, indexing
 by a `N`-dimensional boolean array is effectively the same as indexing by the
 vector of `CartesianIndex{N}`s where its values are `true`. A logical index
-must be a array of the same shape as the dimension(s) it indexes into, or it
+must be an array of the same shape as the dimension(s) it indexes into, or it
 must be the only index provided and match the shape of the one-dimensional
 reshaped view of the array it indexes into. It is generally more efficient
 to use boolean arrays as indices directly instead of first calling [`findall`](@ref).

doc/src/manual/performance-tips.md

@@ -1675,7 +1675,7 @@ as opposed to the later phase when it is first invoked. The parser does not "kno
 The magic of type inference takes place in the later phase of compilation.
 
 Thus, the parser does not know that `r` has a fixed type (`Int`).
-nor that `r` does not change value once the inner function is created (so that
+Nor that `r` does not change value once the inner function is created (so that
 the box is unneeded). Therefore, the parser emits code for
 box that holds an object with an abstract type such as `Any`, which
 requires run-time type dispatch for each occurrence of `r`. This can be