docs: fix offset parameter wording in blas/ext/base sort2 READMEs

Propagates the fix from 618583c ("docs: update copy") to sibling
sort2 packages whose READMEs describe multiple offset parameters using
singular phrasing. The dsort2ins, ssort2hp, and ssort2sh packages each
document two offset parameters (offsetX and offsetY) but referred to
"the offset parameter" in the singular; the wording is corrected to the
plural form already used by sibling packages.

Ref: 618583c

Author: claude

lib/node_modules/@stdlib/blas/ext/base/dsort2ins/README.md

@@ -122,7 +122,7 @@ The function has the following additional parameters:
 -   **offsetX**: `x` starting index.
 -   **offsetY**: `y` starting index.
 
-While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, the offset parameter supports indexing semantics based on a starting index. For example, to access only the last three elements of `x`
+While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, offset parameters support indexing semantics based on starting indices. For example, to access only the last three elements of `x`
 
 ```javascript
 var Float64Array = require( '@stdlib/array/float64' );

lib/node_modules/@stdlib/blas/ext/base/ssort2hp/README.md

@@ -122,7 +122,7 @@ The function has the following additional parameters:
 -   **offsetX**: `x` starting index.
 -   **offsetY**: `y` starting index.
 
-While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, the offset parameter supports indexing semantics based on a starting index. For example, to access only the last three elements of `x`
+While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, offset parameters support indexing semantics based on starting indices. For example, to access only the last three elements of `x`
 
 ```javascript
 var Float32Array = require( '@stdlib/array/float32' );

lib/node_modules/@stdlib/blas/ext/base/ssort2sh/README.md

@@ -122,7 +122,7 @@ The function has the following additional parameters:
 -   **offsetX**: `x` starting index.
 -   **offsetY**: `y` starting index.
 
-While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, the offset parameter supports indexing semantics based on a starting index. For example, to access only the last three elements of `x`
+While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, offset parameters support indexing semantics based on starting indices. For example, to access only the last three elements of `x`
 
 ```javascript
 var Float32Array = require( '@stdlib/array/float32' );